And I think that's fine; Rust isn't trying to be the one language to rule them all. It's intended as a foundational language: your friend's streaming website survives despite his own code crashing often, but it won't survive if his off-the-shelf HTTP server crashes often (HTTP servers being the sort of thing one would write in Rust). Likewise, your mathematicians aren't going to be very productive if their Python interpreter crashes often (likewise, interpreters are the sort of thing one would also imagine writing in Rust).

Even in Rust's ideal future, very little of the code atop the stack is written in it. It's the code at the very bottom that underpins everything whose share it hopes to eat.