And the crazy thing is there is arguably a lot more of a reason for Meta / Oculus to have had its own operating system because it is meant for a specific config

And the crazy thing is there is arguably a lot more of a reason for Meta / Oculus to have had its own operating system because it is meant for a specific configuration of hardware and to utilize those hardware resources to a quite different goal than most other OSes out there. Even in that environment it was still a waste