The overwhelming majority of "high-level language" developers are, at an absolute minimum, familiar enough with C, or C-like languages, to be able to read/contribute to a C project.
Heck, most of us, yourself included, started off with C... it's just how it was/is taught.
Perhaps your C skills get rusty without use, or perhaps you're not a bit-twiddling magician, but you can still read it, and therefore think about it, and therefore write it.
It doesn't limit the pool of contributors... quite the opposite.
Now, if you want to have a debate about a better choice of language for other reasons, that might be fair game... but to imply there's a shortage of C developers is just absurd.
Most of the Python and Ruby developers I know are not comfortable writing C code.
More importantly, there's nothing in the world more dangerous than someone who knows just enough to get something working in C.
C is a harder language to learn than Ruby, Python, or Javascript. Unlike any of those languages, to write in C you have to constantly keep object life cycles, memory hierarchy, and memory layout in mind. Most of the standard libraries of Python or Ruby --- even simple string manipulation --- are idiomatically written and rewritten by hand in C. Even experienced C programmers forget, routinely and to calamitous affect, how machine integers work.
Writing something in C reduces the number of programmers who can contribute to a project.
And that reduction is going to get worse and worse over time. When I started my career, if you were going to ship code to clients, C was the industry standard way to accomplish that. A giant chunk of all working programmers used C as their daily language. Today, only a small minority of programmers will ever once write a production C module.
> The overwhelming majority of "high-level language" developers are, at an absolute minimum, familiar enough with C, or C-like languages, to be able to read/contribute to a C project.
This is completely untrue. My experience with Rust is that many, and likely most, Rust developers came to the language as their first systems programming language. That's one of the main reasons you see so many questions about the borrow checker: it's codifying existing best practices in C and C++, but most developers coming to the language aren't aware of those practices in the first place.
Oh boy, I'm starting to grow weary of folks tirelessly thumping this mantra. It's patently absurd.