What seems to be working is Rust.
As a replacement for C/C++ this makes perfect sense, as a replacement of JS/Ruby/OCaml, not so much.
OCaml has bytecode + native code compiler, both much faster than heavy C++ templated code, or plain Rust code.
I would also say safety/correctness usually win over runtime speed concerns if no other factors are involved as far as Rust design decisions go, at least that’s how it has typically been.