The young woman opposite on the tube last week was lost in Donna Tartt's new novel, The Goldfinch. She personified the truth that attention deficit disorder is a lie. I'm not saying she was weirdly small, but she could have used the 771-page book as a coffee table. She was about halfway through and the covers kept springing back in defiance of her struggling fingers. When she finally got off at Earl's Court she looked like she needed assistance, or a trolley.

Why didn't she read Tartt as an ebook? Why did she choose this inefficient delivery system that proves what Philip Larkin wrote at the end of A Study of Reading Habits, namely that "books are a load of crap"? There seem to be two reasons.

One, the notion of conspicuous consumption developed by Thorstein Veblen. It's not enough to have a yacht; you have to park it at Saint Tropez harbour for the rest of the leisure class to see. It's not enough to read the latest Donna Tartt; you have to read it in public as a marker of your good taste. Even if it gives you a hernia.

Two, books are getting longer in a crazy bid to confer on the literati's waifs an evolutionary advantage over their peers. Books are getting longer, even as articles moaning about our declining attention spans are getting more frequent. Eleanor Catton's recent Booker-winner The Luminaries is 832 pages; the new translation of Victor Hugo's Les Misérables, called The Wretched, which comes out on Thursday, is 1,416 pages. Remember The Little Book of Calm, which was so small you could put it in your breast pocket and bring out when you needed a little soothing or tear it to shreds when its advice became insufferably twee? They don't make them like that any more. Yes, you may think that three of those big books, Stieg Larsson's Millennium trilogy, needed something (an editor?), but that's not really the point.

In a culture of speed-dating, quick fixes, fast food, bullet trains, pop-up everything, and unreadably long jeremiads about the increasing incidence of attention deficit hyperactivity disorder, the single-minded commitment required to read a long, absorbing book serves as a rebuke to a culture that favours those who can simultaneously email/tweet/instant message/hold up their end of a phone call/Skype while live blogging the whole shebang. In 1977, the Nobel-winning economist Herbert Simon warned about the dangers of the looming information-rich world, arguing that "a wealth of information creates a poverty of attention".

No doubt Simon was right, but perhaps we're now witnessing an inversion of that equation: a wealth of attention focused more readily on the things that warrant it. According to Daniel Goleman, author of Focus: The Hidden Driver of Excellence, some Silicon Valley workplaces have banned laptops, mobile phones and other devices during meetings in order to battle the lack of focus that you'd think (ironic face) Silicon Valley's gadgets facilitated in the first place.

Eleanor Catton, winner of the 2013 Man Booker Prize for fiction for all 832 pages of The Luminaries. Photograph: Andrew Cowie/AFP/Getty Images

And it's not only books that are changing. The idiot box is braining up too. University College London recently held a seminar, called Complex TV: Television Drama in the 21st Century, premised on the idea that in recent years, the television drama series has undergone radical development, both in terms of series-creators' ambitions for the medium and audiences' expectations. Hence The Sopranos, Breaking Bad, The Wire, Scandi-Noir, Downton Abbey, Peaky Blinders and Broadchurch. There was a time when TV only earned scorn from academia. Now, according to the seminar's blurb: "Episodic storylines have increasingly expanded into season-long arcs, allowing for a far greater subtlety to narratives, which are no longer dependent upon satisfying the casual viewer." They've become, in a sense, like the TV equivalents of long novels and professors at UCL, the fourth best tertiary educational institution in the world, find that they're worth academic attention.

Why? One reason, according George Potts, a graduate student behind the UCL seminar, is that the best TV series no longer have to pander to viewers' lack of intelligence or want of concentration.

"It seems to me that TV drama has risen to its supreme position because of its unique ability to overcome or buck the trend in the short-attention-span society," says Potts. "It's strange how some series can demand so much of viewers and yet this doesn't put people off in the way that a 'difficult' novel would."

He cites the lack of flashbacks in Breaking Bad as indicative of the tribute its makers paid to viewers' intelligence. An example is drug dealer Jesse Pinkman's realisation, in episode 11 of the show's final season, about what had happened to the ricin cigarette (a key item in the unfolding drama of betrayal). Saul had earlier pickpocketed the ricin cigarette. "There's no flashback, no initial explanation – all the viewer is offered is Jesse gazing at a cigarette packet as a reminder that in the previous season Saul's assistant Huell had pickpocketed him in exactly the same way."

Why is that significant? "The lack of flashback for such a key scene and the confusion it can and did cause is my favourite example of how television no longer feels the need to pander to viewers," says Potts. "Given that Breaking Bad's audience kept increasing until over 10 million tuned in for the US season finale, this clearly paid off."

But why would TV be in a unique position to buck viewers' short attention spans? Potts cites the rise of online viewing, Netflix and Sky+. Viewers have been given tools to instantly rewatch and make sense of these unprecedentedly complex narrative arcs. "In this, I'd say complex television is taking the place of the novel we used to read in bed at night." Maybe. Or maybe long novels and complex TV are two faces of the same zeitgeist-confounding phenomenon.

Perhaps, in any case, longer novels and complex TV series are not the only countervailing forces against short-attention-span culture. Maybe, just maybe, music is rebelling against its cowellised rihannificaton. Does James Blake winning the Mercury prize with a difficult record amount to a Gaga-reflex against homogenised music? Let's hope so.

Yes, but how many copies of these long novels that frustrate instant gratification in favour of richer experience actually get their spines broken? Don't they sit on your shelves like good intentions along with Proust, Tolstoy and Hegel's Phenomenology of Spirit? According to my estimates, of those of you who bought David Foster Wallace's Infinite Jest, only 37.25% have read it. And don't some series sit on your hard drive, unwatched and reproving, while you watch reruns of Horrible Histories or You've Been Framed? Maybe that's just me.

David Sexton, the London Evening Standard's literary editor, reckons "long novels are having a moment", but it's more than a moment. This time two years ago the Guardian's John Dugdale noted that the "craze for long books goes on and on". That season the must-have bricks of paper were George RR Martin's latest fantasy whopper, A Dance with Dragons (1,040 pages) and Haruki Murakami's 1Q84 (just under 1,000 pages). And Stephen King's 11.22.63 had just landed – at 740 pages shorter than its predecessor Under the Dome (1,074 pages), but long enough to make reading King's oeuvre a full-time occupation.

So why is there a trend for longer novels? As Kevin Pickard, an English student at the University of Oklahoma, recently noted, Philip Roth augured as much in an interview in 2004: "I don't think in 20 or 25 years anyone will read these things at all. I think it's inevitable. There are other things for people to do, other ways for them to be occupied, other ways for them to be imaginatively engaged, that I think are probably far more compelling than the novel, so I think the novel's day has come and gone."

Nearly a decade on from that prediction, the inevitability of the novel's obsolescence seems fanciful. They're not so much disappearing as taking up ever more space – even if a growing proportion of that is in cyberspace.

Why? "It is one of the paradoxes of our age," wrote Esquire's Tom Jonud recently. "We complain that we don't have any time. Our storytellers proceed as if we have nothing but. Our directors seem incapable of making a movie less than two and a half hours long, our novelists of writing a book less than 400 pages … In journalism, what used to be characterised as 'narrative' or 'literary' or 'new' journalism is now described simply as 'long form', as if length were the trait that supersedes all others."

So what's going on? One theory (mine) is that the lure of the long is a revulsion at the zeitgeist, a desire to live in a different way from the one that dictates that everything can be expressed in 140 characters or fewer: long books, TV series and unbelievably protracted journalistic pieces meet a demand. And that demand is kindled precisely because our attention spans have become shorter as a result of the increased claims upon them. We want an out from an unsatisfying way of being. Especially if it involves, say, an immersion in the interiority of a character (the descent of Walter White, Don Draper, maybe even Thomas Shelby). We want to spend time on one thing, rather than fracturing time incessantly, making it thereby unendurably meaningless.

James Gandolfini in The Sopranos. Photograph: Allstar/HBO

What's striking is that some figures show that those most likely to read are not old people but those aged 18 to 24: in the US, at least 88% of 18-24s have read a book in the past year, compared with 68% of over-65s. It's young people, traditionally viewed as the irresolute, attention-lite problem, who – more than the rest of us – don't like the way our culture is working.

Pickard, who is 21, wrote in his article: "It's painful to hear people talk about my generation. The 'millennials', according to the critics, are a generation of addicts, our thumbs permanently scrolling through the flashes of text provided by Twitter, the ostentatiously antiquated photos of Instagram, and the pretend sociality of Facebook."

Still, cool name. The Millennials. There are lots of less nice names for those immersed in unedifying multitasking reality. The vampire novelist Cassandra Clare dubbed them the Mundanes; you could also call them the Wretcheds. Here's another: the Desultories, those who yield to the attention-fragmenting technological strictures of our modern world. The Desultories, those whose brains, neuroscientist Susan Greenfield worried, are possibly being rewired with shortened attention spans and loss of empathy, because they spend too much time online. The Desultories, those whom Maryanne Wolf, cognitive neuroscientist at Tufts University, argued are losing the brain circuits honed by reading books and thinking about their contents as they spend more time on computers. "It takes time to think deeply about information and we are becoming accustomed to moving on to the next distraction," says Wolff. "I worry that the circuits that give us deep reading abilities will atrophy in adults and not be properly formed in the young." Atrophied, superficial, unempathetic, pointlessly hyperactive – who'd want to be a Desultory?

In that sense, the desire to read longer novels is understandable. It's akin to the desire to write them. "I love having an alternate life to retreat into and to lose myself in," Donna Tartt told an interviewer recently. "I love being away from the world so long – so far out from shore. Eleven years." It doesn't take 11 years to read The Goldfinch, but it takes some commitment.

David Sexton noted that when he was reading the ebook version of The Luminaries recently ("I couldn't face carting such a heavy object to and fro every day." Wimp) his Kindle measures his progress by percentages. "In the case of The Luminaries," he noted, "that means you can read for ages without seeming to make any progress at all." It's that big. But how nice, in a way, to be so lost in a forest of text that you don't seem to make any progress in your journey out of it back into the real, and really boring, world. That said, Sexton was happy when he hit 100% and finished the bloody thing: The Luminaries was, for him, written by a "juvenile Kiwi AS Byatt". Ouch. AS don't buy it, more like.

No wonder, either, that Netflix has done so well since it established itself in the UK last year: it dangles before us an escape from an irksome world. After you've watched one episode of Parks and Recreation, up pops a little box on screen saying the next episode starts in 12 seconds. One more episode wouldn't hurt, would it? Five hours later Lesley Knope is your role model; you want to lose your fingers in Ron Swanson's luxuriant retro-moustache. Then you dimly realise that you've forgotten to pick up your kids from school and/or that the beeping noise is that your boss has texted you 12 times wondering if you're planning to show up today.

Perhaps subscribers have yielded to this importuning pop-box so readily as an antidote to the short-termism of the Desultories. And perhaps technology, which helped us become desultory and unfocused, also now facilitates greater concentration and focus.

In Civilisation and its Discontents, Freud saw humanity oscillating between freedom and security. Today, nauseated by desultory freedom, we are flipping back to security – the long book, the immersive TV series, experiences deeper and richer than posting your "likes" on Facebook. Hey, maybe in future even marriages will last longer than they do now, as we get tired of the gimcrack claims of sexual novelty? Yeah, right. Let's not go nuts.

• This article was amended on 22 January 2014. An attribution for material taken from an article by Kevin Pickard should have appeared earlier to make clear that a reference to Philip Roth's comments about the future of the novel came from his article.