Rust won’t even succeed at replacing C++. There are technical and cultural issues at play. C++ has evolved a lot and still does some things better than Rust (dynamic linking, for example). Rust will be another popular systems programming language. There will be better ones. People will take their picks.
I find C++ friendlier for small hobby projects because it lets you get your code compiled even if it's a little messy or slightly unsafe.
As for "serious code", I admit that Rust is maybe better for low-level security-critical stuff. But for native applications it's on par thanks to smart pointers and also just -fsanitize=address.
(also default copy semantics just seem more intuitive i dunno why)