C++ historically had much more implementations. It is probably more about the availability of quality compilers that are free to use and adapt, because even in C most new compilers for niche platforms are now based on GCC or clang for the practical reason.

Both implementated in C++.

As someone that remembers the t-shirts with "my compiler compiles yours" that some C folks used to wear, it is kind of ironic having that turned around on them.