There's nothing all that new about what will happen (if it doesn't fizzle out), technology has advanced before. What's threatened isn't the art world with all it's mysticism and tax evasion, but the current shape of what you might call the commodity visual arts industry; gig-economy commission stuff, but probably even moreso stuff like graphic design in advertising. That whole sector will realign around the new socially necessary labour-time and division of labour involved in producing certain visual outputs. As always with capitalism, that process will screw over some of the workers in that industry just like it has done with scribes, typesetters, draftsmen, and a thousand other trades.

The way that existing art is stolen and reused in the process is somewhat new though, in just how much it alienates art from artist. At least with things like stock photography libraries there is a theoretical system of royalties and licensing to give the actual creator some kind of credit/compensation. I'm sure there will be new additions to copyright/trademark/IP law, but only in service to those capitalists best able to lobby for and profit from them. Even an ideal system, e.g. where inclusion in the training data is voluntary and the AI tools find ways to asign credit through to the works drawn from, still sounds hellworld and would probably lead to the data getting filled with SEO-hacked garbage trying to farm the system.