The reason there is no npm/maven for C, is because UNIX culture prefers Makefiles and packages on whatever format the actual UNIX implementation uses.

Depots on Aix, pkgsrc on Solaris, tgz/rpm/deb on Linux, ports on BSDs,...

In any case, I would argue that we have npm/maven for C, and C++ nowadays, via CMake/Conan/vcpkg.