No amount of fallible human vigilance will stop you from forgetting the existence of a C++ quirk in the code you're rushing out before heading out for the night. Human oversight does not scale.
Rust solves 1 category of problems in a way that is not without its costs and other consequences. That is it. There are projects where this is very important, there are other projects where its virtually useless and the consequences just get in the way. It is not magic. It doesn't make anything actually 'safe'.
That being said, Rust is really about lifetimes. That's the big ticket selling point. My point above was that 1) it isn't a silver bullet and 2) it can be a real hindrance is many applications.
I bet there's easily tens of thousands of times more C++ code than Rust code out there.