One could make the same point about any rust that ultimately interfaces with the system using libc - all Rust programs at one point were interfacing with a lot of C code.
A more serious counter argument is that Mozilla did exactly this with Rust in Firefox - and it seems to be a success, there's still lots of Rust in the browser and it seemingly is working.
Point being, using Rust for all of the things will probably be painfully cumbersome today, but writing up a complicated enough component with a well defined boundary with the rest of the kernel will probably prove immensely useful and won't be painfully cumbersome.
A more serious counter argument is that Mozilla did exactly this with Rust in Firefox - and it seems to be a success, there's still lots of Rust in the browser and it seemingly is working.
Point being, using Rust for all of the things will probably be painfully cumbersome today, but writing up a complicated enough component with a well defined boundary with the rest of the kernel will probably prove immensely useful and won't be painfully cumbersome.