I doubt generative AI music is going to become popular as anything but background noise, but I think it will plausibly cut into various commercial uses of music in ads and whatnot.
So while I don't think people are gonna be walking around with playlists of AI slop, businesses will be using it as a cost-effective option, which means it will be eating away at the gig potential for artists in the low-to-mid layers of the food chain. Which sucks, but is thankfully less grim than everyone just preferring the AI slop for some reason.
It's plausible to me that there is some kind of strong AI future scenario in which they become capable of making things in a genuinely creative way, but I think generative AI in its current trajectory is ultimately a dead end for both AI art and strong AI.
I do think that an actual strong AI would be inclined to make art that is enjoyable to itself and other AIs, not humans, so I don't think making it ape us is an actual good test for when an AI becomes capable of creativity.
You can teach a dog to dance, but it will be doing a trick, not a tango.