Yeah, and we're slowly slowly moving towards that model. One barrier is that some safe languages, like Rust, support far fewer target platforms than the Linux kernel does. There are C compilers for everything, but only a few Rust backends.
Something similar to Wuffs[0] (posted on HN very recently), which compiles down to C, might be a good compromise between portability and safe languages. (There may be some contorted way to have Rust emit C, too.)
Rust uses LLVM, which likely should have easier time being ported than an entire Rust compiler. Rust handles cross-compilation pretty well so you don't have to compile on an actual embedded device, or something.
I wonder if an LLVM backend that issues a very simple and predictable subset of C would be a viable way to support exotic old architectures which only have a C compiler. LLVM-cbe is a thing: https://github.com/JuliaComputing/llvm-cbe
