This type of "packaging" is completely orthogonal to module systems. It's merely a syntactic discipline that adds one more complication to deal with even where it has zero benefit.

You could say that the C/C++ systems already has "modules" if you look at object files and header files. Of course, they are a limited kind of modules because they are a bit low-level and C has the preprocessor problem, making it slow to "import" modules. But none of that has to do with namespaces.