As someone who has done kernel development work (though not Linux), not every part of a kernel is as filled with dragons as you make it out to be. Why would my e.g. filesystem driver need to punch a lot of deep unsafe holes down to the internals of memory management? Why can't I make use of a safe abstraction implemented using unsafe code to free myself from caring about those details?

With C, you can only do these kinds of safety guarantees with a lot of discipline. With Rust, you can offload much of your discipline to the compiler.