Why is it harder to bootstrap a self-hosted language than it is to bootstrap a language implemented in C, which itself must be bootstrapped?
Bootstrapping is a one-time cost, but implementing the toolchain in C is a cost everyone has to pay every single time they touch the toolchain source.
What additional cost does it have to implement the toolchain in C? I would say there is some benefit in terms of implicit testing to have a compiler self-hosting. But having a toolchain in C also has real benefits.