Earlier quoted context omitted.
> The choice that people want is the ability to have other App Stores, or direct installation. Who do you want to pay for building and supporting this functionality? Apple presumably?
Yes. And? Microsoft does that for Windows, and you know Apple already does it for MacOS right? Anyone who wants to list on the App Store can could still continue doing so and pay directly. The fees right now don't make sense anyway as many apps are free while others have to pay a cut for services that Apple has nothing to do with.
Possibly that experience led them to not do it when they had the clean slate of iOS.