The argument that the App Store has helped a lot of developers and the argument that Apple's cut is to high are not mutually exclusive.
Once a certain fraction of all software globally is sold over your platform and you reach an overwhelming market power (a point that Apple and Google have passed a long time ago), you have to accept the responsibility that comes with it. You're not just responsible to your shareholders. You don't get to keep 30% of every transaction ever made just because you own the platform.
Before the App Store, taking 30% of anything as a digital platform was unthinkable. Imagine if Microsoft had done the same with Windows. Imagine if VISA and MasterCard took 30% of every transaction just because they provide the platform. Everything would be a lot more expensive for consumers only for a handful of corporations to get even richer.
It's just greedy, plain and simple.
I really don't understand why people are defending Apple so fervidly on this topic. It's really not good for anyone that Apple takes such a large cut (same goes for Google, etc. of course). It's not good for developers, it's not good for you as the consumer. It's only good for Apple.
All of you people always complain about Apple's prices for their devices being too high (Studio Display, Airpods Max, etc.), but at the same time you're all going head over heels to defend Apple's taking 30% of every transaction.