Who said they are? The GP's language is "foundation of an entire industry"; I would argue that you and I could both find plenty of industries that directly attribute their foundations to those languages.
In what way Ruby and Python are foundations for entire industries? As I see, these two are just surface level languages which mostly use C/C++ under the hood.
Rails and Django alone account for a disproportionate number of current software service companies. That’s just what immediately comes to mind.
“It’s X under the hood” is true, but only in the same sense that “computer programs are made of coffee” is true. You can’t easily replace a Ruby stack with a Python one just because both have a reference C implementation; that’s the entire point of having high level languages with rich abstractions.
