The other thing is that human-created art evolves and changes and develops over time. AI “art,” if it becomes dominant, will just be the same thing over and over because it’s always created from a dataset that’s static except for the inclusion of increasing amounts of its own pastiches.

You are wrong there, apparently these models when trained over and over on similar datasets (like their own output) will eventually collapse into weird stuff, called model collapse. See: www.techtarget.com/whatis/featu... So it is actually worse.