It's probably much simpler than that. C/C++ are lower level programming languages (Assembly and machine code being even lower). It means, that they are much nearer to how computer's CPU / GPU / APU / MCU operates.

Languages on top bring human convenience to that. Because that is easier to do that than to invent new type of computers (though historically there were attempts like Lisp machines, Forth machines, now neuromorphic, etc).

The pyramid looks like:

AI-powered-language-to-be-invented-yet, ...

Python, ...

C / C++

Assembly

Machine code / microcode

Thus, the reason why C / C++ is important is that the developer can understand one level more of the pyramid. Learning Assembly can give a little bit more (though less because C is already low-level enough), and "learning" machine code does not bring much (it's almost 1-to-1 with Assembly) unless you design hardware.

Understanding adjacent levels can be equally beneficial with pyramids of frameworks. E.g. React developer better know JavaScript.

Next.js

React

JSX

Javascript