You could. But now you are trusting an entirely new toolchain that can build the Rust-based linker, even if it is statically linked. This toolchain is much larger than a comparatively small and much more easily understood C bootstrap toolchain.

This effectively triples or quadruples (maybe even more) the amount of code you need to trust for the cold bootstrap.

Why do you keep saying C? Mold was C++ with some dependencies like TBB or zstd.