This year's retrospective pop music marketing push has been stuffed with commemorative Nirvana magazines and guitars and a documentary on two decades of Pearl Jam that premiered at Toronto International Film Festival. The year 2011, we've been endlessly reminded, marks the 20th anniversary of grunge – or at least the year Nevermind and Ten were released. But beyond the consumer recycling, there's a reason grunge still retains meaning. Unlike their hipster successors of the early 00s, grunge rockers were actually angry.

What you notice, listening to the spokesmen of grunge – particularly Kurt Cobain and Eddie Vedder – is that they didn't want the Seattle scene to turn out the way it did. There's the feeling that something went horribly wrong somewhere along the way, and that if only it had been kept under wraps, hermetically sealed and locked away in Seattle forever, it could have been saved.

In an interview Cobain gave only months before his suicide, he told journalist Michael Azerrad, "I've always felt like my generation was the very last innocent generation. Everything was a total fantasy, everything was just very basic, just medieval compared to things nowadays." The Seattle kids could see it coming, whatever it was that happened after the city was set upon by Naomi Klein's "coolhunters", when it was packaged and shipped off to the far corners of the world as a prefabricated trend. Despite their alleged feud, Vedder and Cobain both worried about selling out. It was exemplified by what at the time seemed like hypocritical whining: Cobain's reluctance to allow Courtney Love to buy a Lexus, or his overt musings about how In Utero would be hated; Vedder's annoyance that his image was used without his permission on the cover of Time, or Pearl Jam's fight against Ticketmaster's monopoly.

For a brief moment after grunge hit it big, it was possible to see where that relative innocence (or the fight to retain it) was lost. It was part of what made grunge bands unique: their conflicted, angry lyrics were often manifested to some degree in real life. They had a genuine annoyance with the status quo, and the only solution was to scream about it into a microphone. None of that anger is anywhere to be found in the hipster rock revival of the early 00s. Modern rock isn't emotionally vapid, but there's an inherent cynicism, an exhausted acceptance of the system. Even a track like Arcade Fire's 2004 "Rebellion" is immediately qualified parenthetically with "(Lies)". If Cobain's generation was the last with any innocence, then this generation is perhaps the first that never had any.

In his book Retromania: Pop Culture's Addiction to its Own Past, Simon Reynolds argues that the very hipster crowd set on making the kitsch cool and reviving the dead aesthetic of past decades ought to be the exact people moving culture forward. Maybe, but then again, it's been a weird decade for the first post-postmodern generation. Gen Y is forever cursed to account somehow for the event that will always define it: the 9/11 terrorist attacks and its subsequent memory, which is now equally destined to be revived and revisited until it, like so many hipster fads of late, is summarised entirely by an online meme generator casually uploading the words "Never Forget" for ever and ever.

How prescient it was, then, that the album that reignited rock'n'roll would be the non-committal "Is This It" by the Strokes: an entire generation summed up in a phrase stamped on an album recorded only months before 9/11. A decade later, accelerated digital media has perfected premature obsolescence. By the time anything is new, it's already old, replaced immediately as the chattering mob moves on, endlessly devouring more information while producing less and less meaning. All this in the face of ceaseless war, high youth unemployment and a looming economic shit storm.

In this context, hipster nostalgia makes a crazy sort of sense: rather than summon the energy for a defining statement of anger or outrage, Gen Y has only mustered a shrug, and waited as the consumerism that grunge initially fought off washes over.

"It's sad to think what the state of rock'n'roll will be in 20 years from now," Cobain told Azerrad. "It just seems like when rock'n'roll is dead, the whole world's gonna explode … it's already turned into nothing but a fashion statement and an identity for kids to use as a tool."

Rock'n'roll has gone from a linear derivative art form to an abstracted, nominal designation. It's not dead, just more or less spent.