Uhm, this is clearly trying to follow Google's Android with clear previous inspiration from Apple. I don't see how this is anything like what Microsoft or Epic does.
That said, the Apple strategy has clearly failed them so far, so now they try it a bit more Google like, neither of which is good for the users.
And the original argument from Carmack also has a gaping flaw. If software is the main problem and evidently Meta can't solve it in house despite throwing practically infinite money at it, the only solution is to open up the software and let others experiment with it and contribute to it.