Kubernetes is a lot like java. It was cool when it was young but then became a lawyer. Glassy eyes, fat, full of pedantic details and insanely boring.
Also similarly to Java EE and the likes you can create a black hole by amassing all the resources and books written about them in one place. Some believe this has already happened.
Seriously now. Kube first and foremost was/is the final attempt of google et all to curb AWS. I don't think it has much to do with productivity for any small/medium company out there that is dragged into its complexity. But it's very hard to not drink the cool-aid.