I think this would be a strong point if commissioning the store was the primary means of income for apple. But apple strategically uses the fees to attack their competitors. Squeezing spotify for example with a 30% fee while at the same time pushing out apple music for a ~30% lower price.

That in my mind is not a content agnostic platform seeking to make money as a service provider, but leveraging a platform to attempt to gain monopolistic power by force.