Comment by XorNot

This entirely depends on the supposition that there are more new kernel developers who want to, and are able to, use Rust then C.

I don't think this is proven: what we have is a specific group of Rust developers, but they are there by virtue of that group existing. There are numerous more kernel contributors today who work in C, and since the greybeards are happy to keep up the work it's not like anyone else is going to easily step in to replace them (since it would be a coup not a handover, if they didn't actually want to step down).

An equally plausible future is some such Rust mandate happens, you drive off the existing C developers, then it turns out the Rust developers aren't actually numerous enough or committed enough (or even good enough at long term project social management) to keep the project going and it dies (or forks into CLinux or something).

Linux itself was a "hobby project" which ultimately succeeded because it did the work which needed to be done, while everyone else was still completely sure the microkernels were the way of the future.