I'm not sure that's true. A couple of years ago sure, but Rust is growing very fast.
I also think there's no reason to think C will stay around forever. The C ABI will be the lingua franca, but that doesn't mean you need to actually use C.
The only reason it has persisted for so long is lack of alternatives, but now we have at least Zig and Rust. Obviously there's a ton of momentum so it will still take a while to be replaced but I wouldn't be surprised if e.g. musl switches to Zig or Rust fairly soon.