Reach for the current issue of Private Eye and you will find "Bookworm", the anonymous author of the magazine's Books & Bookmen column, indulging his or her fondness for schadenfreude by rounding up the worst reviews of this season's crop of new books. The writers mentioned will no doubt simply shrug – or perhaps grimace – to have readers' attention drawn to less than ecstatic comments, especially when numerous glowing reviews are ignored. But "Bookworm" also has a few sharp words for those whose work is undertaken outside the glare of publicity: "it's not only the authors who will and should wince on reading these words. The editors . . . are responsible as well, for being too indolent, timid or unobservant, if the reviewers are right. But will pain spur them to remember that editors are supposed to edit?"

Editors are supposed to edit: well, of course. What else would they do? And why should Private Eye, in the process of tweaking a few authors' noses, alight on those who labour behind the scenes and accuse them of incompetence? The answer lies in the changing role of the editor, in the turning wheel of the publishing industry and in the expectations of readers.

One evening at the end of last September I found myself all set to interview Jonathan Franzen about his new novel, Freedom, on the stage of the Southbank Centre in London. I had anxiously worked and reworked my list of questions, but while my preparation was not in vain, it was swiftly put into perspective by an unexpected turn of events. It transpired that Franzen had that very afternoon, during the filming of a BBC television programme, discovered that the UK edition of his novel contained a number of errors – errors that he thought had been corrected during previous stages of production. In other words, the copies of the novel stacked high in the foyer, not to mention the tens of thousands on their way to bookshops, were not as Franzen, or indeed his publisher, intended. In the green room at the Southbank Centre, a clearly shaken but phlegmatic Franzen outlined his plan to tell his audience – and, by extension, the reading public – of the unfortunate development and to urge them to wait to buy the corrected edition. When he did so, there were – an unusual moment for most literary events – gasps of shock, followed by a nervous silence.

It seemed like something from a (rather heavy-handed) novel itself, and it was certainly a gift to headline writers; not only was Franzen's previous novel entitled The Corrections, but that book's US edition had suffered similar teething troubles. And, in a pile-up of ironies, one section of Freedom goes under the heading "Mistakes Were Made". But the affair also cast an intriguing light on our curious relationship with literary texts, on the authority we feel should be vested in them, and on the obvious but somehow occluded reality that books are, to a greater or lesser degree, the result of a collaboration between writer and publisher. Franzen and his publishers had a horrible although mercifully rare experience, but it was not one entirely without amusing side-effects. One was the number of people – including me – who had read advance copies of Freedom and failed to notice errors, whether straightforward typographical slips or stylistic infelicities. But despite the hoopla over Freedom, in truth it had very little to do with the day-to-day business of publishing, bookselling or, indeed, writing: Franzen, one of the literary world's heaviest hitters, has extraordinary care, attention and money lavished on his work.

But what happens the rest of the time? Away from the world of freak glitches, what fate befalls the writer as his or her magnum opus enters the publishing production chain? For some years now – almost as long as people have been predicting the death of the book – there have been murmurs throughout publishing that books are simply not edited in the way they once were, either on the kind of grand scale that might see the reworking of plot, character or tone, or at the more detailed level that ensures the accuracy of, for example, minute historical or geographical facts. The time and effort afforded to books, it is suggested, has been squeezed by budgetary and staffing constraints, by the shift in contemporary publishing towards the large conglomerates, and by a greater emphasis on sales and marketing campaigns and on the efficient supply of products to a retail environment geared towards selling fewer books in larger quantities. In more broad-brush terms, the question is whether the image of the word-obsessed editor poring over a manuscript, red pen in hand, has given way to that of the whizz-bang entrepreneur attuned to the market's latest caprice, more at home with a tweet than a metaphor.