I can't speak for Rust, but for Go the answer is easy: Go programmers. That is, why implementing the full Go stack in Go was such an important step, there is li

I can't speak for Rust, but for Go the answer is easy: Go programmers. That is, why implementing the full Go stack in Go was such an important step, there is little C left in the toolchain, and consequently, C programmers are not needed for most of the development.