I don’t think those have much to do with it.

Certainly Go is a more rigorous language than say JavaScript but it’s package mangement was abysmal for years. It’s not even all the great now.

C/C++ is the same deal. The way it handles anything resembling packages is quite dated (though I think Conan has attempted to solve at least some of this)

I think Cargo and others have the hindsight of their peers, rather than it being due to any rigorous attribution of the language

Tacking package management onto a language is feature creep to begin with. You can pretty obviously have a program in one language that uses a library or other dependency written in a different one.

The real problem is that system package managers need to be made easier to use and have better documentation, so that everyone stops trying to reinvent the wheel.

Yes, we can even see—the languages with the best culture and superior rigor have the best package manager: C and Fortran, which just use the filesystem and the user to manage their packages.