The app store offers subscriptions. If you subscribe to, say, netflix or hulu using an ios app, apple collects 15-30% of the subscription revenue. Netflix fairly publicly killed the app store subscription payment method in the beginning of the year because of this.
That was just the point. At no time did you have to go through the App Store to get s Netflix subscription. You could always go through the Netflix website.
Netflix chose to use the App Store as a method for payment even though they didn’t have to. They decided it was worth the trade off. Plenty of subscription services decided it wasn’t from day one.