Can someone explain to me what the difference is between AI art and students imitating an artist?

Students are people who cannot truly copy art even if they wanted to. Pius, everyone generally does art their own way because... that is the point of art.

Image generation models just copy patterns from existing images, there is no process of artistic creation, nothing to interpret, no process... AI generated images are just pretty noise.

What happens when the AI actually gains the ability to experiment "outside the box" - what we call creativity?

It cannot do that just by design. It's not a thinking thing, calling these models AI is really a misnomer and more of a marketing thing than a description of what it really is.

Then the copyright system needs to go away.

The one is done by a human, the other by machine. People are in general more interested in other humans doing things. We watch people play chess but not really machines, even though the later are better. We admire craftsmanship, but automated assembly line doing extreme precession work is just rather functional. I think it has something to do wit empathy and how we relate to other humans rather than to inanimate objects.