I really don’t get these memes. In about 9 years of daily use on multiple systems I never had anything break beyond a multitude of failures to update with pacman - all of which could be fixed within minutes - and in the early years having to restart my system every couple of months because it stopped recognizing USB devices - after many rounds of updates mind you. I’ve had more frequent troubles with windows. How did Arch get this bad rep?
The kernel is probably too large to rewrite the whole thing at once. This could lead to a future without any new C kernel devs, leading to stagnation, while the Rust kernel could be many years away from being finished. (Assuming we actually move away from C.)
At that point you might as well just start an entirely new kernel and hope it is good enough to eventually replace the Linux one once all devs are gone. Kinda the X11 and wayland thing.