Why did modernism/avant-gardism fail to endure outside the academy?

I often encounter people, not necessarily on this forum but elsewhere, who insist that so many modern novelists write as if we're still living in the 19th century and Ulysses never happened, and they cite people like McEwan as the object of their ire and wonder why people aren't reading say Thomas Bernhard instead. Is this a justified position or misguided? If you think about it, it seems as if early to mid 20th century modernism and/or avant gardism doesn't exert much influence of modern-day "literary culture" as the *chattering classes" conceive of it. Why aren't writers like Bernhard, Handke et al. household names in the way Kafka and Woolf are? the prominent 'serious' writers of the late 20th century like Marquez, Pamuk, Ishiguro et al. are approachable for an 'educated middle class' readership. But then at the same time, an AG writer like Ionesco isn't that 'hard to read', even if the school of writing to which he belonged hasn't really endured in the collective imagination of again 'literary culture' unless one maintains a keen interest in mid-20th century absurdism. Likewise Jean Genet. I get the impression that names like Joyce and Beckett are prominent even if the work remains almost only of academic interest. Is it a sign of aesthetic regression that the most well-known serious writers of the late 20th century such as Marquez seem to be drawing inspiration from a more traditional classical paradigm while figures such as Bernhard, Genet, and Ionesco remain more of a niche interest and aren't perceived as *the major figures of late 20th century literature* or is something else at play as well. Is the conscious attempt at formal experimentation in someone like Bernhard simply too clinical, in turn robbing it of any sense of humanity that one may find in the more chattering classes-friendly Latin American Boom writers, for instance?

So I suppose the question is if modernist/AG values no longer steer the ship of contemporary literary culture from chattering classes perspective the way they did in the 1930s, is it a sign of aesthetic regression or not necessarily?

*The major writers of the late 20th century* don't seem to be building on what those early 20th century modernists were doing or on what mid-20th century avant-garde writers like Beckett, Ionesco, or Genet were doing, which, as a result, leaves them in the dust or at least seems to do so.

Then again, perhaps the main thrust of literary culture simply hasn't caught up with the likes of Ionesco and Genet yet, making them ahead of even our current epoch, which explains why they only remain of interest to those keenly drawn to absurdism. Perhaps we'll reach a point where they're household names just like Chekhov or Flaubert. Who knows? After all, Moby Dick wasn't canonical until a few decades after Melville died.