That's what happens when the language has "history". Of course when they design a new language they try to incorporate all the features that developers demand

That's what happens when the language has "history". Of course when they design a new language they try to incorporate all the features that developers demand at the moment in a way that makes sense. But once the language is developed it is difficult to add new features seamlessly. The new features are necessarily impaired in some way by having to be compatible with existing environment. Rest assured, wait couple decades and the same will happen to Rust.