It is analogues discussion to C vs Rust. Sure Rust is memory safe, but whole ecosystem I am using today is C based. Compiler, SDK, drivers, RTOS, ... Nobody sane is going to rewrite it for the sake of rewriting it into a different language.
I would disagree with that comparison. Rust really does provide an improvement in memory safety that is hard to achieve by other means. That's not to say you should always rewrite in rust, there are plenty of situations where that doesn't make sense. However its not analgous to the performance situation in my opinion.