You mean Microsoft proactively kept shooting devs in the kneecaps?

Leaving phones behind on old incompatible OS versions 2 times in 3 years and switching app frameworks 3 times in 4 years does not a good app developer experience make.

Piled on top of that, Google became actively hostile to 3rd party developers building support for YouTube (and Gmail and Gmaps, but those had workarounds / alternatives).

What about running the whole Android infrastructure, but on top of a non-Android Linux distro? And this, on top of a Android kernel (otherwise you won't have the drivers yo uneed)

The advantage being, we can manage packages using a regular Linux distro

App support, stable ABI, uniform UI/UX, hardware vendor cooperation...

I dont think app support is all that important. Most apps are garbage as they are ime, so rebuilding from scratch, or using existing software that runs fine on linux, would keep me happy.

Microsoft could, but abandoned just as they gained traction in Europe

Doesn't windows run android apps natively now?

Microsoft can barely pull off their flagship desktop operating system, so that doesn't say much.