John Carmack's arguments against building a custom XR OS at Meta

I think people have forgotten about Google Fuchsia which I guess is a good sign for a new OS. They’ve done quite well in deploying it seamlessly to their consumer devices.

"Quite well" by what metric? It shipped on one device. That's pretty much the lowest bar you can imagine! Did it provide any tangible benefit to anyone? Let alone a benefit commensurate with the enormous cost of developing it and continuing to maintain it?

I think it was insane to start a new OS effort written in C/C++. We have plenty of OSes written in C/C++! We know how that story ends. If you're going to spend the effort, at least try a new language that could enable a better security model.