A person sitting in an art school/museum for a few hours ingests way more than just the art in question. The entire context is brought in too, including the artists own physical/emotional state. Arguably, the art is a miniscule component of all sensory inputs. Generative AI ingests a perfectly cropped image of just the art from a single angle with little context beyond labelling metadata.

It's the difference between reading about a place and actually visiting it.

Edit: This doesn't even touch how the act of creating something - often in a completely different context - interacts with the memories of the original work, altering those memories yet again.

And how is any of that a compelling argument regarding the assumption of a fundamental difference in the MO of learning?

Simply stating "it has more inputs" doesn't describe the human learning model, so nothing in this establishes a baseline for comparison.