By the composer, yes, but the composer here is the AI. In neither case did the musicians that the composer studied/trained on get asked.

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.