Pretty much. At least when a human bases their "take" off of someone else's, it still possesses their unique touch and it's neigh impossible to perfectly replicate the take of another.

That's not the best analogy. Your argument assumes that everyone must use drawing processes like professional artists use in order to make art. Rough sketch and lineart may be good for human but not for AI.

Also, if someone does make an algorithm that uses the training data but combines it with the same process that professional artists use (drawing a sketch, then lineart, then coloring), then according to this analogy, this should be a fair game.