Rust is replacing C++ in several well documented places, however C++ itself was a replacement for C in many places. So by definition the use-case for Rust overlaps the use-case for C.
Arguments like this sound like old arguments that were re-told to me by my father where people argued that C couldn't replace the use case for Algol at the University of Michigan MTS system. (Assuming I'm remembering the second-hand argument right. I'm a second generation software engineer.)
Also, there's nothing of note in the last 10 months about Rust that's different from the 10 months before that.