I recently bought some books on Amazon (as I often do--at a pace of approximately 4x the speed at which I've been reading them). Anyway, one of the books was a 4/5 condition used book, which I did not notice during my impulse buy. No big deal, I'm fine with used books.
However, this did occasion the thought, "Does Amazon even care much about books anymore?" They now sell pretty much everything under the sun,
have approximately 65 million Prime members at $100/yr, are the main e-book platform (with prices usually similar to hard copy books), have a film/tv production company, grocery delivery, etc.
These days Amazon seems more than happy to point you to a third-party used bookseller than to sell you a new book, likely because the margins are better and they don't need to carry the inventory. Anyway, I've long considered Borders and Barnes & Nobel dead, but I would be surprised if book sales are more than 10% of Amazon's business these days. It's a juggernaut in many areas, and if it cares about books it's partly due to nostalgia (though they no doubt make bank being America's Monopoly Bookseller(TM).