I think it's more analogous to if you had tweaked one of those famous works directly in photoshop then turned it in. The model training likely results in near replicas of some of the training data encoded in the model. You might have a near replica of a famous photograph encoded in your head, but to make a similar photograph you would recreate it with your own tools and it would probably come out pretty different. The AI can just output the same pixels.
That's not to say there aren't other ways you might use the direct image (e.g. collage or sampling in music) but you'll likely be careful with how it's used, how much you tweak it, and with attribution. I think the weird problem we're butting up against is that AFAIK you can't figure out post-facto what the "influence" is from the model output aside from looking at the input (which does commonly use names of artists).
I work on an AI image generator, so I really do think the tech is useful and cool, but I also think it's disingenuous (or more generously misinformed) to compare it to an artist studying great works or taking inspiration from others. These are computers inputting and outputting bits. Another human analog would be memorizing a politician's speech and using chunks of it in your own speech. We'd easily call that plagiarism, but if instead every 3 words were exactly the same? Hard to say... it's both more and less plagiarism.
Just how much do you need to process a sampled work before you need to get permission of the original artist? It seems to be in music that if the copyright holder can prove you sampled them, even if it's unrecognizable, then you're going to be on the hook for some royalties.
