but no language can take the place of C
Why do you say that? I definitely think Rust can take the place of C. Not just can actually, I'd go as far as to say that Rust should take the place of C. C is much too unsafe to be used in today's age. There's really no excuse to use a memory unsafe language today if you're starting something new.
It would not have been better if it was written in C. Rust is just as fast and much better.