I think that probably has more to do with the fact that Rust libraries basically all come from the same place, since there's been centralized package management

I think that probably has more to do with the fact that Rust libraries basically all come from the same place, since there's been centralized package management since the very early days. It's a lot harder to support something like that after the fact than designing for it in advance; new languages like Rust have an advantage in that regard.