Yet it's Go that added big language features recently (generics, iterators, changing semantics of for loop) and not Rust. Rust hasn't gotten any new major features since adding async ~7 years ago. Rust is much more stable language-wise than Go, partly because it had much more features in 1.0, and Go has to gradually add them (what's next? enums?). It also has much more advanced mechanisms allowing to both evolve the language and not break existing code (editions). Things that neither Go nor Scala figured out yet.