C does not give you full control. Modern C compilers are extremely complex beasts, that do all kinds of unexpected optimizations. They also are limited in what optimizations they can perform, due to the fact that C code can't express things like ownership. So C compilers have to be pessimistic in many situations.

Rust just as fast as C, and gives you just as much control. But if you choose to use the safety features, it's far safer. The only reason not to use Rust instead of C is if your particular tool chain just doesn't have Rust support.

Comp-sci has moved on. C has simply become almost entirely obsolete, in a similar way to how raw assembly is almost entirely obsolete.