On the other hand, a lot more books are published now. There are a lot of books, especially in the genre of experimental literature, that are stranger and more difficult than this. I'd classify Infinite Jest or any of the Irving Welsh books as more ghoulish and harder to read, and those are almost mainstream compared to some things.

Popularity is another matter, but then literary fiction has never been popular, almost by definition, compared to genres: romance, mystery, etc.