For all your complaints about lack of a stable ABI, when you run Linux on a PC most of the hardware just works, most of it without out-of-tree drivers. (In some areas like graphics proprietary drivers give you a better experience, but even there typically there is some baseline support in tree.)

The reason this is possible on the PC and not on phones is because there are more standard hardware interfaces that don't exist in the ARM world. The lack of that is why the phone vendors need to do a lot of custom work.