[Fronzie]

It's partly a historical reason as well. There are many projects with very complex Makefiles. Those are hard to integrate into your own project.

Header-only is the other extreme: No makefile at all. With package managers like Conan and vcpkg, using a build-system like e.g. CMake, it's possible to have very simple and short project files which are easy to integrate.

In this regard, C and C++ are a bit behind the times compared to other languages.

[tonyedgecombe]

Isn't C++ supposed to be getting proper namespaces soon?

[throwaway8941]

I am not an expert in C++, but there exists an opinion that it will not help as much as you might think.

https://cor3ntin.github.io/posts/modules/