Because people don’t want to listen to robots. There was a radio station here in Norway caught playing AI music to save on royalties, it was not good for them.
AI music on a radio station doesn't really make sense. The point is to be able to create custom music tuned to your own tastes -- music that's specifically for you.
The concept of AI music is extremely polarizing. One friend I played it for got visibly angry. Oddly none of the anti-‘s were musicians themselves.