True. And of course there is no problem with other stores like fdroid.
But somehow google play is different, which is why I added the highly integrated part.
I think fdroid actually helps google play by going so far the other direction that it excludes most apps, so you cannot have fdroid as your only app store. (to be clear I highly approve of fdroids policy and would not change it)
But there are even other app stores that cover both bases, allowing all the non free apos from play store and yet not being google. But then the problem is trust. I trust the apps in say the ubuntu repos and in fdroid, but say Aurora store? ehh, maybe? I would normally not even slightly consider installing apks from a 3rd party like that, but I got an eink tablet that can't install google play, so was more or less forced to try it just on that device. But that's not my phone. I don't have or do anything important or sensitive on it.
So while I am still sure that Google is doing multiple things that keep play store practically unavoidable necessity, it's probably also a combination of other, kind of coincidental factors too like fdroids strict principles and no obvious basis to trust any other store. Maybe some of those other factors are not immutable.
Maybe it's just an impression thing or a failure of marketing and Aurora is exactly the answer and exactly as trustworthy as any official major linux distro repo, and I just don't have that impression for some reason.