Just a quick thing I’ve noticed…
When I see (p)reviews of iPad OS 15, nearly every one says complains about the lack of an Apple weather app or calculator.
When I hear people talking about the all the legal complaints, they all talk about how Apple’s apps unfairly crowd out 3rd party apps.
What this suggests is that real people want 1st party apps from Apple, not to have to figure out what other apps are worth using.
I think for many, if not most, users who’ve chosen Apple products already know why they’re using them - Privacy first, intuitive design, etc. Forcing Apple to make things harder for those users seems like an invasive overreach.
P.S. As a technical, Unix-centric user, I will use Apple’s apps over others in nearly every case. I’ve tried many 3rd party mail apps, on macOS, iOS, iPad OS, Windows, and Linux, including some design winners heaped with praise, and none have been as stable, elegant, fast, as Mail.app and their iOS compatriots. The same with Calendars, with Terminal on macOS, with Safari, and on down the line.
There are categories where I do far prefer a 3rd party app. I use pcalc across all devices it’s available, Overcast for podcasts (including on macOS now via M1 macOS-iOS availability, emacs for a nearly everything dev over Xcode (bearing in mind I don’t dev for Apple languages yet, so that might change). I’m not against using 3rd party software, but in nearly every case where Apple has turned their eyes to a thing, their creations are the best of any breed.