I don't understand this idea at all. Everything POSIX exists inside the the kubernetes containers, so it should be thought as a layer on top, not a replacement. I don't think anyone thinks that kubernetes abstractions replace concepts like files, processes or threads like in the diagram presented.

Hey, I wrote the post. Agree completely with your comments. I was trying to draw an analogy between the two, not imply that one replaces the other

Unix scales complexity. Kubernetes is unnecessary complexity.

why we are not unix without kubernetes?

Just no.

why?