Full disclosure: I generally like apple products and have used NeXT / apple products for a long time. I don't see how Apple's stance here is defensible or honest. They using their position as a large platform provider to steal from 3rd party developers. To me this is akin to me writing a program for OSX that allows users to sign up for a subscription service, and apple taking a 30% cut of my cash flows just because I…
Apple has created a ecosystem in which it is very easy for consumers to purchase subscriptions. They're further enhancing the usefulness of this system by blocking applications that do not allow consumers to easily purchase subscriptions in a uniform way (e.g. in-app). And they're requiring app developers to pay 30% for the benefits they receive by exposing your app to the users of this ecosystem.
The rate may be high, or it may not be. We will see by how many developers pull their apps from the AppStore.