I’ll explain ...
Apple deeply cares about two things, (1) user experience and (2) user privacy.
Today, Hey iOS when downloaded IS NOT FUNCTIONAL if you didn’t know to already sign up for the service on their website. That’s a horrible experience and no one likes it. Especially Apple.
On Trust/Privacy, Apple is safe guarding users CardOnFile data with all of their advanced security features that they have worked directly with the major card networks that no small developers (or even frankly medium or large developer) could compete with. This benefits the consumer by reducing fraud, and not having your credit card data sitting in some developers data unencrypted. Apple also helps auto update cardonfile data when the card expires so that the developers don’t lose revenue just because of expired cards.
As for the 30% fee, why shouldn’t they get a cut? If the App Store was a physical brick and mortar store Like BestBuy, I guarantee you then BestBuy wants to make margin on products they allow in their store. (A) it’s a distribution channel to a consumer you as a developer don’t have, (B) there’s hard costs to putting your product in the App Store “shelf” and (C) Apple is providing all of the easy and secure payment processing on behalf of thr developer.
Note: I’m not trying to be combative. I’m just playing devils advocate and pointing out this topic is way more complex than others are making it out to be.