I think in that case, and also without getting too into the weeds, I'd put forward that a precursor to art would be consciousness. Until then I figure it's pattern matching—or instruction-following. Origin I guess I also consider important... but we'll get into the weeds if I do go one (as I was about to start questioning if a child learning drawing techniques from a 'how-to' book is creating art in that moment)

That's my quick first thought, anyway.

Yes - the real medium of art is culture itself. "Content" is just a means to that end.

AI is culturally blind, tone deaf, and dumb. So although it's going to be capable of generating adequate content at some point, it's not going to be changing the foundations of the cultural currents around it in the way a groundbreaking work of art does. (And no - producing "content" mechanically is culturally trivial. It's a change of medium, not a change of message.)

That won't happen until it understands and can influence cultural processes as a personality with agency and something original to say, and isn't just spinning its wheels on MIDI notes and virtual paint splotches.