You can't just "transpile to C" to get "C speed". C speed comes from low overhead. Naive transpilations will just include that overhead, like garbage collection or many layers of pointer indirection, but written in C. The unsavory answer is that you must use less abstractions if you want fast code. Compilers just aren't good enough to compile all the abstractions away.

Yeah I think Zig in particular is trying to be just exactly a "better C".

I don't know if transpiling will get you there, because for instance if you're transpiling a dynamic language, you're going to have to output C that is essentially emulating all those dynamic language features, so it might be faster than say, the original Python, but it's not going to be as fast as a pure C implementation.

> Transpile to C?

If you transpile something to C it does't mean it will be fast. You can write slow C code (or transpile something to C that will be slow). The compilers are not the issue here.