That's not quite equivalent, but I will indulge you. The truth is, there are many tools and libraries written in CPP, with many years of accumulated knowledge implicitly embedded in their codebases, that will take a very long time to replace, if some of them can be replaced at all.

It's fitting that you mention PHP, because while the ecosystem isn't quite the same, for all it's problems (especially security), WordPress is still viable for a bunch new projects, and things may remain that way for many years to come.