Yes, PyPy is an excellent example of doing low level tasks in a high level language. It's also quite rare. I think in the future we'll see more examples of self-hosting dynamic languages that have a JIT-compiler based execution environment that combines interpretation and compilation.
However, in comparison to the stuff that the PyPy guys are writing, C programming is easy. And I bet all of the PyPy programmers are excellent C programmers, because they have to be good with low level stuff anyway.
I still advice learning C programming, and how interpreters and compilers work.
Oh, you are certainly on point. But how deep down the rabbit hole do you want to go? I mean, after reading "Trusting Trust", you really can't be sure of anything. Who writes your compilers? Assuming you are not specifically referring to security stuff, and more talking about a responsible community; well, I don't know. I do know that I need to get better at C. And that that was w/r/t interpreter comment, in case that implication was not obvious.
This is why (good) computer science studies generally involve everything from CPU fundamentals to operating system programming and compiler design. I'm not afraid to look inside my interpreter, operating system kernel or my C compiler.
And, look, I'm relatively new to the game, so please forgive my ignorance when it appears - although I definitely get what you are saying with this comment.
True, but who is going to write your Python/Ruby interpreters then? And using what language?