There are novels that wear well over time, but not all that many, because too often authors are locked into their “present,” whether through social conventions, marketing requirements, or reader expectations.
Jane Austen has enjoyed a revival because women, in particular, have enjoyed her accurate, trenchant, and well-written observations of social maneuvering in a particular time period, an analysis which is transferable in ways to current society, which illustrates how, at times, the “simple” approach of good writing can, in itself, be timeless – but only if it also somehow speaks to readers. And in a strange way, Le Petit Prince, by Antoine de Saint-Exupéry, also has a sense of timelessness, at least in the original French.
Strangely, it seems to me, timelessness is harder to come by in science fiction. A number of once-popular SF novels of the 1950s and early 1960s are also hopelessly dated by technology. Venus the green planet has been supplanted by Venus the lead-melting hellhole. We now know that the Barsoom of John Carter never could have existed on Mars … and there’s also less enthusiasm for honorable but clearly patriarchal heroes of that mold. That, of course, doesn’t stop intrepid “SF” authors, for whom the latest authorial trick has been to invent an alternative universe or history conducive to the pulp-style tales they want to tell.
I obviously have no problem with inventing alternative universes, but I do wonder why such authors would want to create a pseudo-pulp solar system based on concepts popular in the 1920s, 30s, and 40s. Then, again, I suppose that’s a form of timelessness, where modern science has been excluded. At the same time, calling the stories in such universes “science fiction” is a bit of a stretch, but SF has seen survived such stretches and will continue to do so, especially since the limits of hard science are increasingly inimical to space-operatic swashbuckling.
Still, despite the limits of hard science… some science fiction novels, such as LeGuin’s The Left Hand of Darkness, or Zelazny’s Creatures of Light and Darkness, have a certain timelessness, but such books are comparatively rare. Joe Haldeman’s The Forever War, while dated in the sense that we still can’t do what he theorized, has its own sense of timelessness.
Fantasy is much more suited to timelessness, especially with such works as Tolkien’s The Lord of the Rings, but it’s a bit early to tell how time will treat The Wheel of Time or any of my fantasy series or those of other best-selling or acclaimed authors. We may turn out to be timeless… but it’s more likely we’ll merely be authors forgotten in time, which is the fate of the majority of authors.