Of course there’s no way to know for sure, but I would be more inclined to use Rust for projects where the domain is well-understood; however, Kubernetes was (and to an extent, still is) experimental and rapidly evolving. It would be painful to have to do all of that iteration in the presence of a borrow-checker. And yeah, I understand the purported benefits of having a robust type checker protecting you in a refactor.

That said, Kubernetes isn’t a monolith so it doesn’t need to be all-or-nothing, and one component that would likely be well-suited to Rust is etcd.