All our linux kernel module and driver development have been using Rust for a while. I've written a Linux kernel module in Rust that we use in production, and so have many others.

What the Linux kernel is discussing is how to integrate these kernel modules and drivers into the Linux tree. They are not discussing whether this is worth doing, but how to do it. Linux is quite stable if you stick to the right APIs, and maintaining these out-of-tree is not too bad, but the current situation is not sustainable in general.

For us it doesn't matter, because our code is not open source. But it matters to quite a bit of people.