I sure didn't buy a license for every book and screenplay I've ever read. And I borrow a lot of books from the library. I'm not understanding why you think ML models need to license all of their input content when humans clearly do not.
ML training doesn't work without having a copy of the data (books and screenplays). That data can either be copied in a non-infringing way (buy the books; acquire a license) or in an infringing way (download the books from a corpus without explicit permission like these AI companies are accused of doing). LLM services need a license just like Facebook, Instagram, etc. need a license to republish the stuff you post. The copyright holder maintains their copyright and the service that republishes their work (Facebook, Instagram, etc.) or publishes derivative works (AI) needs a license.