Comment by gpm

Linux is a cooperation between numerous companies to develop a shared artifact that works with all of their hardware, solves all of their use cases, etc. No one company involved can just go make their own replacement, because they need the cooperation of the other companies involved to get it to work on the hardware manufactured by the other companies.

Even ignoring the driver problem, it's not really an economically viable amount of work. Right now everyone benefits from everyone else's bug fixes, from everyone else's security improvements (like introducing rust!), etc. Going it on your own means you have to redo everything everyone else has done (unless you just fork linux), and that you don't get the benefit of everyone else working on the shared codebase (I suppose unless you fork linux and keep merging in upstream... which is actually what projects like Android do).

A complete rewrite also means a huge time lag before you start seeing payback in terms of faster development speed and a more reliable/secure operating system. Unlike introducing rust in new work to the existing kernel which sees relatively immediate payback.

I suppose I wouldn't be too surprised to see a project like Android just maintaining a whole series of rust changes in their own branch if the RFL project continues to be impeded by the maintainers. That's what Asahi linux (Linux on apple computers) is already doing (and poking at the android-mainline branch it looks like there are some rust additions that aren't in Linus's tree... but I'm not sure what the extent is).