What cannot programmers manage without knowing the C programming?
Well. You cannot go low to the metal without knowing at least 4 languages of which case C is a part. Youll be unable to write drivers that interact with the kernels resource manager and the hardware. You wont be able to do systems programming or making or dealing with graphics APIs, but other than that there aren't a whole that is special about it other than the fact that it was the first portable assembly language