That's kind of my point; the code might not be as beautiful as we could ever imagine, but as a product it works extremely well, and would be worse if it carried around a lot of runtime baggage and poor performance which many of the alternatives would have given.
This is not about beauty. It is about reliability, simplicity and safety, all of which contribute to development velocity.
Golang is simple only for toy examples.
At scale Golang codebases are difficult to navigate, understand and test due to the repetitive repetition of repetitious repeats.
And the idea that at-the-time-viable alternative languages like Java, C++ or D are too slow for something as relatively lightly trafficked as the core Kubernetes controller codebase is just plain silly.
When I mentioned speed, I obviously wasn't ruling out C++ on that basis - but I would rule out Python or Node. Java is fast enough when going but the awkwardness of needing a JVM plus abysmal runtime memory usage make it pretty unattractive to me, especially for the k8s agents where the resource needs have to be subtracted from total node size.
I've not found Go difficult to navigate because of repetition. Quite the reverse really - it's easy to reason about where everything comes from and (usually) easy to work out how everything connects together. I would take that any day over a large Java codebase with the usual obfuscations of dependency injection, or a Python or C++ codebase where somebody has tried to be "clever".
