Its about consumer rights, about competition, and monopoly practice's that harm the end user.
It's only about Epic wanting more money.
Consumers can choose between different phones with different OSes and storefronts that come with overwhelmingly the same games, so there is no monopoly in the smartphone market. If a consumer doesn't like Apple, they have multiple other viable options. iOS sits at ~25% market share.
EDIT: As for you edit, one of the exceptions for in-app purchases on Google Play is music, so what Apple does with their music app is in accordance with Google's rules.Last edited by RolStoppable - on 13 August 2020