C does have a few indirect advantages:
it is easier for "mere mortals" to write parsers and compilers and similar for it (whereas a "reasonably complete" C++ compiler is a much bigger undertaking);
it has a simpler set of ABIs which are more consistent between compilers, making it a little more reasonable to interface with C from ASM or dynamically-generated machine code, ...
granted, some of this can also be handled via 'extern "C"' as well (so the tools can mostly ignore that they are interacting with C++), or via a C++ subset, but this has a few other issues (now it is more necessary to qualify which sets of features are supported, ...).
this is not to say that everything is perfect in C++ land, as on the internet, one can usually run into lots of (usually pointless) arguments about elements of coding style.
in C land it generally tends to be a lot closer to a "whatever goes" mindset. granted, a person can do so in C++, but then get hated on a bit more than if they did so in C, where one mostly just gets looked down on for using the "archaic" C language.