Of course they can block root access I guess...
Of course they can block root access I guess...
It's my understanding that what's included in open source Android (AOSP) is FAR from a complete product and there is quite a bit of Google closed source/proprietary software that goes into the mix before it's shipped as Android (think Google Services.)
So, while you could fork AOSP and try to use that as a basis for and alternative mobile OS, it would require quite a bit of work on top of the AOSP code. This is what's done by custom ROMs like GrapheneOS (ironically Pixel devices only) or LineageOS for example.
LOS/AOSP/whatever users are a VANISHINGLY small minority of users, so "an app that only works on them" is an app that only works for a tiny minority of people. This would disincentivize developing FOSS apps altogether. A lot of projects will likely eventually die, and a lot that could have started will not.
Other companies like Motorola require you to phone home to unlock the bootloader and we saw how well that worked out for LG where once they shut down that effectively preventing devices from running custom ROMs and having root access. The biggest hurdle is that the overwhelming majority of users don't sideload software. So they aren't concerned about this at all. So all Google has to do is hold against some power users and hope there isn't a mass exodus to LineageOS or GrapheneOS. Which is highly unlikely.
The trouble is, I'm like a 5% of 1%. Most people don't run their own e-mail/calendar/contact servers. We're a tiny breed and there are very few Linux phone alternatives (e.g. PostmarketOS, PinePhone Pro .. Purism is a scam company that hasn't refunded hundreds of thousands of dollars and can go die in a fire; fucking scumbags!).
The Ubuntu Edge failed to get funding back in the early 2010s and very few devices run Ubuntu Touch.
The SoC/ARM model (no standard architecture, some DeviceTrees if companies fell like it, random pins soldered to random chips) makes it very difficult to get Linux adoption on mobile devices like what was possible on PCs.
It's a mess. The US failed by not forcing Alphabet to split Chrome or Android. The anti-trust suit results were a joke.