> And the ones spanning generations were completely fair game.

No they weren't. Copyright at this point covers things for at least half a dozen generations back, and is intentionally made annoying enough that it is difficult to find out what is covered and what isn't. LLM companies didn't bother with any of that (they just pirated like your average online 13 year old), meanwhile archive.org got sued for pulling the music off ancient wax cylinders.

Clean up and dramatically shorten, restrict, or even eliminate copyright, and we can start talking about what's fair game or not. People were afraid to sing "Happy Birthday" in movies for probably 80 years, and the corporations that own all IP made it very clear at the time that they preferred for the status of "Happy Birthday" to remain unclear, and would send you a scary letter if you used it.

> probably going to depend on whether AI is a transformative use.

It's probably going to be entirely political, and decided through corruption. It's obviously a mechanical transformation. If rap DJ's got sued for cramming songs full of 80 extremely manipulated samples that you'd need a forensics expert to trace, and all sampled music had to revert to a form where they'd license a single song and re-release it with somebody rapping over it, LLMs are a violation. DJ's were doing an absolutely creative translation, and LLMs are not creative, they are Δ-following pinball machines.