Don't forget that K8s changes rapidly so whatever you learned a year ago might be completely useless now. So better keep those people dealing with K8s learning by all means or have fun with broken production.
That is not true, based on my experience. I started to learn and use kubernetes about a year ago (now we are running our production systems on kubernetes) and we are usually on the latest version. I cannot mention anything which I learned about kubernetes and because useless, because something changed.
It's less true now, but a lot of older blog posts and books (at the time, even the most recently published books) talked about managing via replica sets instead of deployments. That was a major source of confusion for me when I was getting started.