That’s mission was never to replace C or C++, it’s true.

From the very first introduction of Rust to the world: “a complied, concurrent, safe systems language.”

Then it was “memory safety without garbage collection”.

Now it’s “A language empowering everyone to build reliable and efficient software.”

Sure there is domain and design overlap, but the goal was never explicitly attracting C or C++ programmers. At least not exclusively.

There was a mission statement before any of those that went something along the lines of: "Be much better at building a browser with than c++ is"

That is still Mozilla's main angle on Rust, but Rust has grown much beyond Mozilla, so this is just history now as you describe.

> They aren't interested in the things C++ programmers are interested in.

This assumption only holds if people didn't want to do systems programming before. Many people who wanted to do it crashed into C++ and then said "yeah okay, not for me", which calls this into question.