The art has to be printed out and that is the art. Anyone can get an image of Salvator Mundi for free too. That is not the art, that is an image. The art is the physical object that is the painting Salvator Mundi.
It is no different than traditional art really, just at a different scale. You can buy really nice Picasso knock offs on ebay right now. Picasso himself could have made 10 copies of the Weeping Woman to sell without that much effort either. The "real" Weeping Woman is the physical painting that Picasso did not make a copy of. The others are just knock off images.
But the main problem remains. Selling art is really hard. AI art is already completely passé anyway. If anything the technology is regressing visually.
Music was in a several decades long bull market in physical media sales that crashed and burned. Now we have gone back to the pre-music media bubble days but with much better distribution and marketing channels.
Not a lot of people making a living playing ragtime piano or hoofers making a living tap dancing either.
The real amusing thing to me is you never hear scultpure artist complain that they are in the training data sets. Probably because they know it is literally just free advertising for their real art.