Rust competes with both GC languages (offering way superior performance) and with C++ (offering safety and modern language features).
It’s a pretty strong value proposition, but it doesn’t mean there aren’t good reasons to pick a GC language if you can afford the performance hit.
The list of reasons to pick C++ over Rust is very short, mostly momentum, recruitment, and legacy. For greenfield projects, the list is even shorter.
The general experience is that developing software in Rust is slightly more expensive compared with, say, C#, and way, way cheaper than C++.
I get the sense that Rust is probably a much better replacement for C++ than C, and that Rust discussions frequently devolve because C programmers and C++ programmers are talking past each other, without understanding the divide.