I would say kubernetes is very simple, in the same way lambda calculus or composing programs out of pipes is simple.
It has very simple basic model, which allows you to recursively built more and more complex abstractions on top of it.
It has very simple basic model, which allows you to recursively built more and more complex abstractions on top of it.
There's trade-off between a tool being too specific to a usecase vs being too generic with the associated "boilerplate". But I don't know how much simpler Kubernetes could be made while still covering the intended scope?