Shortly after Anita Brookner's death, Penguin reissued most of her novels with new covers. Most, but not all. Two novels from the 1980s, A Friend from England and A Misalliance, were missing, but they had been out of print for some decades. I don't know why exactly - except that in an interview in the 2000s Brookner described her early novels as 'crap', and also that she said disparaging things at least about A Misalliance at the time of its publication.
But from the 2016 reissue there were several surprising absences. Where was Leaving Home, or Visitors? Visitors (1997), in particular, has always been considered very highly. 'Almost certainly a masterpiece' - as Brookner once said of another author's novel.
I notice similar things happening to the likes of Kingsley Amis. His novels, following a period of neglect after his death in the 1990s, have been reissued under the Vintage label: period classics. But not everything is there. I don't find two late novels, The Russian Girl and The Biographer's Moustache. Are they not vintage enough. Both are very entertaining, the former especially. Both have the sort of extended drunken scene that no Kingsley Amis novel should be without.
In these ways an author's oeuvre becomes fossilised. In this manner, likewise, wider canons are established. Take the nineteenth-century as represented by Penguin and Oxford World's Classics. All of Dickens, George Eliot and the Brontës are available, but other novelists must suffer the selectiveness of the modern eye. Thackeray is a big loser. Only Barry Lyndon (because of the film) and Vanity Fair (because it's Vanity Fair, I guess) are in print. Even Henry James, a much more fashionable author than Thackeray, isn't completely available. His Confidence hasn't been seen for many years. The case of Trollope is interesting too. He had a vogue in the 1980s and 90s, and Oxford at one point had editions available of every one of his forty-seven novels. But now we're back to the basic rump of the Barsetshire and Palliser series, plus a rather random batch of standalone novels.
Recently I've been reading Sir Walter Scott. Only about half of his novels are in print, and the criteria for selection fascinates me. Why Old Mortality but not Woodstock? Why Kenilworth but not Fortunes of Nigel? (I think The Fortunes of Nigel is probably disregarded because of its distinctly risible title.) Of course everything is now to be found online, ready to be downloaded on an e-reader. But sometimes one wants the guidance and consolation of a scholarly editor - especially with Scott.
The future probably isn't bright. Economic factors play as much a part as literary taste or judgement. I can foresee only a gradual shrinking of the canon.
Let me finish with Samuel Richardson's last novel, Sir Charles Grandison, out of print for some decades. It was very popular in its day, and Jane Austen's favourite. A World's Classics edition was available in the 1980s, but it has never been re-released. It now sells for silly prices.