That being said, Getty is hardly the paragon of goodwill considering they regularly steal from public domain databases, issue DMCA takedown requests of the stolen content from said databases, and then turn around to sell it to unwitting people for a subscription. They own none of the copyrights for what they are doing but have been allowed to get away with it.
There are public domain works you can use and copyright doesn't protect ideas. It protects expression of ideas, so getting "just the ideas" without the expression is ok.
The problem is that "expression of ideas" in the realm of AI is akin to plagiarism by human standards, because its a literal copying of the source material blended together. I couldn't recite you the entire plot of the Odyssey off the top of my head literally, but AI can, because it has the source material. We just tell it to do funny ha-ha things so its okay.
What’s the legal distinction between you learning and AI learning?
I'm not distributing my brain, at least same (but probably more restrictive) should apply to models - training is okay, but using and distributing should be limited by copyright
Besides which, "learning" isn't a fair use exemption anyway.