Not all of us see C++ as an improvement over C.

Sure, C++ has great advantages, but it also great disadvantages.

I use C for many things not because of "macho", but because C is good enough. I can work around the disadvantages using standard techniques. The result is code that is easily FFI'able from any language, quicker to compile, has a smaller footprint, sane error messages, easily debuggable in gdb, etc.

Also, there are some advantages in the abstractions that C encourages you to use. For example, lack of templates pushed C programmers to discover intrusive data structures, and those are better in many ways than templated containers ala STL.

Another example: "virtual" methods may fail to override a base class method if you make a typo - resulting in potentially cryptic bugs. Using a simple macro in C:

  #define MAKE_VTABLE(prefix)  { prefix##foo, prefix##bar }

I can make vtables that are safer than C++, and require no more boilerplate than C++ code. The compiler will guarantee that I implement all of the required vtable methods.

If I want to get speed via multi-core rather than pure uniprocessor speed, why use C++? I can use Haskell and get much easier and safer parallelism with many other advantages.