>Without licenses to the books, they are just as illegal (and maybe even moreso) than web content.

There are books that are out of copyright, and also free books.

If LLM organizations are free to throw billions at hardware they can spare a paltry €50 million for 10 million e-books though, right?

€50 million is about 130% of OpenEuroLLM's budget. And I'm very sceptical publishers will give training licenses for €5 per book. Especially as OpenEuroLLM intends to have an openly available training set.

Copyright sucks.