You’re definitely right in terms of arbitrary OS installation, some folks have got Ubuntu running on Lenovo snapdragon laptops recently.
The lack of “portability” though is a bit troubling, it seems each device (tree) has to be manually added, developed, tested, and have an install image created for it, unless I’m missing something. And this will be arduous and potentially problematic for corner cases or small numbers of adopters of a particular machine model (so basically the same as right now I guess).
E