> Furthermore, I don’t think you can really assume that the courts will rule a certain way on this just because of the money involved; there’s a lot of money involved when it comes to the copyright holders too, and they’ve long enjoyed a rather favorable status with the courts and legislators.
I don't think this is all that plausible, even though I agree with you that it's not settled law. The size of the AI industry is gigantic, and a ruling that they are infringing the copyright of every piece of content in their training set would essentially shut them down entirely. Such a decision, if final, would probably easily wipe out a few hundred billion dollars on the stock market. Even if any court was willing to go that far, almost certainly lawmakers would step in and modify copyright law to prevent this from happening - both in the USA and the EU.
I don't think there is any comparison to make with the file sharing battle. That was a much, much smaller industry, it was not a significant chunk of the total hardware and software industries. Plus, the software titans were not nearly as well connected politically as they are today.