Not all books, of course - but the ones that are geared toward passive income. Imagine some guy with a small bot-farm that manages to generate thousands of different "authors", and generate similar books for each and every one of those - then spam the living sh!t out of marketplaces. And then tens of thousands of other people do the same, because they follow the same tutorial.
Before you know it, there are millions and millions of different books on the same topic, all somewhat unique - in the sense that they've been generated by a LLM, and not copy/pasted like in the good ol' days.
It's going to be fun.