Android (to a lesser extend iOS) has become deeply embedded in the infrastructure of modern society. It is essentially a public utility and should be managed as such.
If they don't, they can sideload, and use F-Droid, and etc.
And then we can debate whether it should be default on, or default off, and how hard it should be to turn off.
(I do not use iPhone nor Android and I won't, even if they do fix these problems.)
We also have PostmarketOS (alpine base) and Mobian (debian base) as frontrunners. Supposedly Arch Linux for ARM and openSUSE Tumbleweed are also used by some on mobile.
Edit: Oh I get it, "develop for the platform" means develop and distribute. Maybe it's just me, but seems like an important difference.
Everyone is still free to develop and distribute source code.