[white-flame]

While this would supplant "C for speed" libraries, it wouldn't supplant "C for OS access" libraries. At some point, system code needs to call the OS.

[pjmlp]

Not all OS were or are written in C.

[white-flame]

Sure, replace "C" with whatever OS language is appropriate. The situation is still the same: wasm doesn't talk directly to the host interfaces, regardless of it being low-level. You'd still need another FFI layer somewhere to talk to those.