And yet here we are, able to talk to a computer, that writes Pytorch code that orchestrates the complexity below it. And even talks back coherently sometimes.
There's no need for ongoing, consistent human verification at runtime. Any problems with the implementation can wait for a skilled human to do whatever research is necessary to develop the specific system understanding needed to fix it. This is really not a valid comparison.
Those proprietary blobs are either correct or not. If there are bugs, they fail in the same way for the same input every time. There's still no sense in which ongoing human verification of routine usage is a requirement for operating the thing.
While one can in principle learn C as well as you say, in practice there's loads of cases of people getting surprised by undefined behaviour and all the famous classes of bug that C has.
I believe it to be likely that the C programmer would even writes the code faster and better because of the useful abstractions. An LLM will certainly write the code faster but it will contain more bugs (IME).
It writes something that that's almost, but not quite entirely unlike Pytorch. You're putting a little too much value on a simulacrum of a programmer.