There's no escaping Dickens this year, it being the bicentenary of his birth. And along with Dickens come his illustrators: Cruikshank and Phiz, obviously, but a plethora of others including Richard Doyle, Edwin Landseer and John Tenniel. It's impossible to detach the novels from the illustrations, not least because the author meant it like that. Only Great Expectations and Hard Times were produced without pictures. For the rest, Dickens kept an iron control over his illustrators... he gave them an outline of the plot before he wrote the text and he monitored the drawings to ensure that they matched precisely with his own conceptions.

The tangling of text and drawings was obvious from the start: The Pickwick Papers began with Dickens being invited to write stories to accompany illustrations by the popular artist Robert Seymour; it wasn't long before Seymour was illustrating him. In the other direction, his best-known collaborator, Phiz, controversially took credit for some characters in Oliver Twist.

All of which raises the interesting question of why it is that this kind of collaboration doesn't happen any more. Where is the Phiz to our Boz? Why don't contemporary novels have illustrations as standard? Why are illustrators corralled into children's fiction? Up until the Fifties and Sixties it wouldn't be unusual for a mainstream publisher to illustrate adult books. Now it's easier to count – you don't need all the fingers on one hand – the publishers that do. Is it that contemporary fiction happens all in the head and cerebral stuff doesn't really lend itself to images? Are modern novelists just too precious to collaborate with artists? Is it the additional cost in an already tight budget? Are modern illustrators just not that good?

Dan Franklin at Jonathan Cape is one of the few British publishers who bucks the trend. He commissions both graphic novels and illustration for adult fiction, the latest being woodcuts by Joe McLaren for Andrew Motion's sequel to Treasure Island, Silver, which is aimed chiefly at adult readers. He identifies two reasons why it's not common practice.

"I think a) it's fashion", he says trenchantly. "And b) there aren't that many great illustrators. It's rare you can come across someone who can draw. Even when you're looking for someone to do book jackets, it's hard to find someone who can draw the human figure – it seems to be unfashionable now."

Of course cost can be an issue. Commissioning an artist for a book could amount to £2,000-£4,000; small beer if you're talking about Julian Barnes but a big deal if it's a first novel for which the author is barely paid that much. But money isn't the real deal-breaker.

Simon Prosser, publishing director at Hamish Hamilton, is another publisher who is remarkable in the trade for habitually commissioning illustration for adult non-fiction, possibly because he started out as an illustrator himself. Why aren't there more like him?

"It might be", he says, "that illustration is simply unfashionable. I have a strong, deep attachment to books that were illustrated... I remember from my early reading, the classics of natural history, like Izaak Walton and The Natural History of Selborne and they were all illustrated." Which brings us to another issue, the dearth of publishers with some sort of visual grounding.

Does it matter if adult books are all text? Even the greatest enthusiasts wouldn't say you should illustrate everything. You wouldn't wish on any artist the job of drawing much of Virginia Woolf. But the possibility that illustrations could actually illumine writing and draw out elements of a narrative doesn't seem to count for much any more. And as Posy Simmonds, well-known as a graphic novelist as well as illustrator, observes, illustration can do many things for a novel: "There's lots of choice, whether to interpret, decorate, contradict. It can add to or detract from the writing." She herself has drawn pictures for poetry as well as prose, including Carol Ann Duffy's "Mrs Scrooge".

But there is a problem with the nature of modern fiction. As the novelist Piers Paul Read says, "illustrations are best suited to a novel with a strong narrative, that is to say, illustrating an incident – and there are fewer such novels around. No publisher has ever suggested illustrating one of my novels."

Quentin Blake is a genius of the genre, his collaboration with Roald Dahl being one of those instances of the sum of the whole being greater than the parts, like Ernest Shepard and Kenneth Grahame or William Blake and William Blake. But he didn't start out solely as a children's illustrator. He did book jackets for Evelyn Waugh and Kingsley Amis and illustrated Black Mischief and Scoop for the Folio Society; more recently he did drawings for a new edition of Candide.

He thinks that the nature of modern fiction is a challenge, but not an insuperable one. "Once novelists got into the interior monologue... that's what spoiled it for illustration", he says. "But there are things you could do that we've lost the habit of doing. There's a wrong assumption that you're going to draw exactly what the text says. But it calls for a bit of thinking. You don't always want to see what the protagonist looks like. Are you drawing surroundings, atmosphere, furniture? There are ways of contributing to novels. Commissioning drawing, I think, is a habit as much as anything. One doesn't want to say everything should be illustrated. But there are moments when something very interesting could be done. We've lost the habit of thinking like that."

Yet it turns out that, perhaps because illustrations are such a rarity, many novelists are glad to have them. The Folio Society is the one publishing house for which illustration is part of what it does. Its artistic director, Joe Whitlock Blundell, finds that novelists are usually pleased to collaborate with artists. Kazuo Ishiguro rejected the first drawings he was sent for The Remains of the Day because he felt they were too dark. But he was "hugely pleased and proud" about the final version. Salmon Rushdie liked the illustrations for Midnight's Children so much he bought the originals.

Admittedly some authors fight shy of illustrations, like JD Salinger, or their estates do. But if there is a dearth of drawings in adult novels, the problem doesn't seem to be with the novelists.

Because illustration is now the preserve of children's books, there's a sense that this is where it belongs, with childish things like comics. Or as Quentin Blake says, "there's a feeling it's not quite grown up to have pictures." Posy Simmonds agrees: "there's a sense that pictures are something you grow out of."

This is so not the way things used to be. A remarkable number of the 19th-century illustrators of children's books used to draw for adults too. There wasn't an unholy divide between the generations.

George Cruikshank, of Dickens fame, also illustrated fairy stories like Jack and the Beanstalk and the Grimm brothers' fairy tales. Ruskin said they were "unrivalled in masterfulness of touch since Rembrandt, and in some qualities of delineation unrivalled even by him". Walter Crane, one of the earliest creators of children's picture books, was an associate of William Morris and a designer of stirring socialist posters. CE Brock illustrated E Nesbit but also Emily Brontë and Walter Scott. William Heath Robinson did illustrations for Edgar Allen Poe and Rabelais. Arthur Rackham illustrated Oliver Goldsmith. I could go on.

Some of these were considerable artists, others just jobbing draughtsmen. What developed in the course of the 20th century was, however, a distinction that survives even now, between illustration and fine art, aggravated by the development of abstract art and the flight from drawing.

And that brings us to the other big reason why so many books don't have pictures. As Dan Franklin says, lots of artists can't draw. Or at least, fewer than before. I know, I know, it's the sort of thing the Prince of Wales might say (and indeed why he set up a drawing school of his very own), but that doesn't mean it's not true. If you look at the one area where newspapers still commission drawing – sketches from the courtrooms, where cameras are not allowed – what is obvious is the poor quality of the draughtsmanship. And there are far fewer outlets where young practitioners can make a name for themselves: the line between cartoonists, caricaturists and illustrators is pretty fluid and there simply aren't the magazines that there were in the Sixties, say, that carry drawings and visual satire; Punch used to be the great seedbed for talent and the Radio Times used many artists. No longer.

Chris Beetles is a longstanding enthusiast for illustration, and his gallery in St James's, London, is one of the very few outlets for illustrators. But he acknowledges freely that the modern part of the catalogue for his annual exhibition reads like a Who's Who of artists of an older vintage. "Younger artists patently don't have the drawing skills the previous generation did", he says. "They're much more able to manipulate a photocopier. A lot of the art of drawing has disappeared."

One good reason is that it's no longer taught in the major art schools. Brian Sewell, the Evening Standard's art critic, is trenchant about the problem. " I know", he says, "of no art school that teaches drawing or has any idea of what drawing is and what it is for. I know of no art school that has the slightest notion of its importance. There is one exception, the Prince's Drawing School and that is a tiny little ivory tower. People there are taught by artists with no real reputation. It doesn't count."

His contention is borne out by one of the youngest artists to feature in the Chris Beetles gallery, the 34-year-old caricaturist, Jonathan Cusick. "I studied at the University of Central England, the Birmingham Institute of Art and Design 10 years ago", he told me. "We weren't taught to work in black and white. We were taught some drawing but it's dropped completely off the agenda now. We had one morning a week for life drawing. But that was the only formal drawing we had. It's not widely taught. Older artists like David Hockney would draw from nine to seven at night when they were students. I'd be amazed if there were colleges where that happens."

But it's not too soon to write off the possibility of illustration making a return. And curiously enough, it comes from the very development that people darkly assume to be undermining publishing as we know it: digital technology. Kindle makes the reproduction of colour plates far cheaper than now. As Simon Rossiter observes: "Books are more and more in the digital world – there's a real case for making books more special... it would be great to have a special Kindle edition of a novel." Dan Franklin is even more upbeat: "We'll find in the years to come that there's a renewal of illustration in books. Because of Kindle there's a new impulse to make the physical hardback book a more beautiful object. Illustration will be part of that. And when the enhanced e-book is up and running, it will be part of that too." Indeed a friend showed me an app from the Museum of London with Dickens's Night Walks as an iTunes graphic and audio book, illustrated by David Foldvari. It's brilliant.