It is quite easy for C++ and Rust to both be faster than C in things larger than toy projects. C is hardly a panacea of efficiency, and the language makes useful things very hard to do efficiently.

You can contort C to trick it into being fast[1], but it quickly becomes an unmaintainable nightmare so almost nobody does.

1: eg, correct use of restrict, manually creating move semantics, manually creating small string optimizations, etc...