I think the next big thing is going to be proving the provenience of training data. Kinda like being able to track a burger back to the farm(s) to prevent the spread of disease.

There was an onlyfans creator on a chat group for one of the less restricted machine learning image generators a while ago.
They provided a load of their content, and there was a cash prize for generating content that was indistinguishable from them.
Provided they were sure that the dataset was only their content, they might be able to claim copyright under this.