Somewhat relatedly, there's already a section on "culture", something I think that is sometimes overlooked by language creators. The shape of the initial libraries can shape the entire ecosystem of a language, even when the language itself is technically capable of supporting a different culture.

There's a lot of winds blowing against a new language, but this is one of the rare winds blowing for it; it can literally be easier to write a new language from scratch and boot up a new culture than it can be to change an existing culture. For example, it wouldn't matter if C++ imported every Rust feature, even for the sake of argument to the point where this new (terrible monstrosity of a) compiler could literally compile all current Rust code. The result still wouldn't be "Rust", or able to "kill" Rust, because the sheer inertia of C++ culture (or, for a language this big, "cultures") would simply never produce the sort of code that you see in real Rust.