You are committing the perfect solution fallacy [0]. Rust won't make you have no bugs in your code but don't conflate some number of bugs with a reduced number of bugs, a reduction is still a meaningful outcome, otherwise we'd still be writing in assembly.
> We're talking about control systems, life saving technology, technology that's running in outer space.
Indeed, that's why we should use more memory safe languages, because we are dealing with critical systems. Just because they were written in C does not mean that they should continue to be. It's like digging a hole with a stick, and when someone suggests a shovel or backhoe, you mention that all previous holes were made with a stick. There is no relationship between the previous work and what should be done in the future.
[0] https://en.wikipedia.org/wiki/Nirvana_fallacy#Perfect_soluti...