The app store ecosystem clearly has value, and I think Apple are entitled to make a profit off of it. (See, for example, comments below about how difficult it is to cancel subscriptions to other kinds of services.) The problem is that the 30% Apple charges has no relationship whatsoever to the amount of value that the app store provides - it's simply how much Apple can get away with charging. If alternate app stores were allowed, or alternate payment mechanisms were allowed, Apple would only be able to afford to charge a premium commensurate with how much "better" their experience is.