Exactly. And it also points out how hard it would be for Apple to extract those fees, which conceivably would be difficult indeed. Apple could just deny publis

Exactly. And it also points out how hard it would be for Apple to extract those fees, which conceivably would be difficult indeed. Apple could just deny publishing your app if you didn't sign an agreement requiring you to pay 30% of your externally sourced revenue via your iOS app but the enforcement would now become (mostly) manual, whereas with IAP, compliance with the fees are unavoidable as they all go through Apple's software