Ok you're still missing the point. This isn't about C being good or bad or suitable or unsuitable. It's about whether it's good that C has, through no deliberate set of choices, ended up embodying the interface that lets us build rust that can be called by go.

Yes, because C is, by virtue of its history and central role in the development of all mainstream operating systems, the lowest common denominator.

Also, if I remember correctly, the first Rust and Go compilers were written in C.