I do not disagree with you even a little, and not just because C is my bread and butter. At this point, I am merely curious about examples of large projects doing a successful switch from language A to language B.

I just remembered reading about MirageOS recently. Almost everything is done in OCaml. I am sure it contains a bunch of low-level C code. It seemed interesting, but I don't think such projects will ever replace systems written in C.