As the book digitizes its revealing previously unnoticed schisms between genres, like a kind of fracturing Yugoslavia.
In the past printing words on dead trees was the only game in town, a pre-historic pulp Internet where the packets were books themselves. This created a flourishing world of genres that flowed through this paper Internet: literary fiction, non-fiction, comic books, cook books, textbooks, encyclopedias, and more.
Many of these "books" never should have been books in the first place. For example, encyclopedias always stressed what dead tree paper was capable of. They strove to be authoritative, up to date, truly accessible, both wide and deep, and more. The rise of Wikipedia showed that encyclopedias never made sense on dead paper, at which point they promptly disappeared. Remember how heavy print encyclopedias were? How they never truly covered all topics? How they fell out of date?