What do you mean with "then took the scans home"? Anthropic et al didn't buy all the books in the world and kept them for themselves.
Therein lies the rub: they didn't buy them... They pirated digital copies of them.
See, e.g.: https://www.theatlantic.com/technology/archive/2025/03/libge...
Correct, they torrented them. I just wanted to stick to the library analogy of the parent comment.