Both Google and Apple have kept a stranglehold on the mobile app distribution market for over a decade now.
I completely disagree. I'm not sure how they could make it much easier without defaulting to allowing it. Download the APK, open it, click install (or if the setting disallows it, follow the prompt to change the setting).
Third party app stores on Android are not allowed to compete with the Play Store on feature parity because of limitations put in place by Google.
Again, the only way to implement automatic upgrading, background installation or batch upgrading/installation of apps is via the Play Store.
It is still far better than iOS, and it might get better: I have seen Google employees comment on here that the next release of Android could allow the install apps permission to non-system apps.
It would be a race to the bottom where they all ended up with zero margins but where your data is sold to third parties.
It's the third party app stores that would sell the aggregate data instead of taking a cut off sales.
there already are lots of third-party android app stores, if you look at the variants of android packaged and shipped on new-in-box phones in mainland china.