As someone who has been running kubernetes clusters for the last 1.5-2 years. It's quickly becoming boring (in a good way). I'm at a fairly large enterprise and we're running five clusters (two gke managed, which .. is limiting, three with our own bootstrap). I'd say we spend about 10%-20% of our time actively managing clusters (upgrades, troubleshooting.. some of that time is about maintaining some value adds like automatic log shipping.. that kind of thing), most of our work is writing value-adds, helping customers onboard and consulting with teams on how to best deploy and work with kubernetes (many teams at my company aren't really familiar with containerization).

Granted we run our own bootstrap (when we started none of the bootstraps running around we're ready, we started with a terraform/make implementation of hightower's hardway and we've just kept adding. We're thinking about revisiting the space again.