Multithreaded code is usually bottlenecked by memory bandwidth, even more so than raw compute. C/C++/Rust are great at making efficient use of memory bandwidth

Multithreaded code is usually bottlenecked by memory bandwidth, even more so than raw compute. C/C++/Rust are great at making efficient use of memory bandwidth, whereas scripting languages are rather wasteful of it by comparison. So I'm not sure that multithreading will do much to bridge the performance gap between binary compiled languages and scripting languages like Python.