I think this ultimately just reflects on a certain generation of software that we're still using - a 1990's, Unix-ish, graphics-oriented, Internet-capable stack.

I don't think we're staying there, either. C++ is very long in the tooth. Most people looking for a C++-like thing now gravitate towards Rust(with a little bit of deviation for stuff in roughly the same ballpark like Nim, D, and sometimes Zig). And many of the old projects are looking towards migrating to new languages as well. It's just a matter of the critical masses shifting.