Probably people at some point were making same arguments about ASM and C. How many people though do ASM these days? Not arguing that for now it is relevant point, obviously Rust / C are way faster.
Furthermore writing large programs in pure assembly is not really feasible, but writing large programs in C++, Go, Rust, Java, C#, Typescript, etc. is totally feasible.
C compilers weren't up to stuff, that is why books like those from Michael Abrash do exist.
Depends what you mean, if you preclude using targeted ASM in your C I think some hot loops can be much slower than 2x.
Of course programs globally written in assembly largely don't make sense.