Speaking specifically about cases where any not-completely-trivial `if` is matched with an explicit `else`: I wonder to what extent this code could be simplified if the authors of k8s had chosen to design around using structural pattern matching rather than `if`/`else` blocks?

Lots of mainstream languages with support for structural pattern matching have compile-time tooling to check whether a match was exhaustive, which alone could serve as an idiomatic solution while increasing information density in the code.