I would say that being able to compile code in one language means close to nothing if a developer can't understand how a project is structured and how a component is supposed to work.
Thus, the observation doesn't inform the debate about C and C++ overlap.
There's more overlap wrt mental models between C#, Java and C++ than there is betwern C and C++. Being able to compile code in both languages means close to nothing if a developer can't understand how a project is structured and how a component is supposed to work.