I didn't ask you how they shouldn't get it. I asked you how they should. Like, only one way. Because even on Android, the average user is not gonna use F-Droid and using an apk file is simply not practical for many. Sure, you get users, but if your goal is to make it easier for the majority of the people, they sure as hell will not download F-Droid just for one specific app. Besides that, it is also a market opportunity. I'm sure the devs of these apps also make some good money on these.

As for Apple... sure, there is AltStore, but how many people are using it yet?