And that's the point: The difference is the replacement of 1 flesh-and-blood composer with 1 virtual composer, with the consequence being the lost business of the former. The artists studied were never part of the transaction in either case.
Now, the long-term consequences for artists - e.g., reduced supply on the low end as they're out-competed - is harder to guess, but that's just market dynamics. It may very well increase supply as composition becomes more available, diversifying by allowing people with other skills or creative treats to create music that previously could not - even if the musical part is done by AI.
but with AI whatever consequences there may be their work is highjacked/stolen.
You can learn yourself but if you use an automatic tool to bypass and automatically make similar works and compete with original authors then you're IP thief
That's by choice though?