I think we're conflating Kubernetes with containers here.

I definitely agree that databases don't benefit from running under containers - they are pet-like (and so don't benefit from fast spin up or massive horizontal scaling) and tend to require host-level tuning (which breaks the container abstraction).

What Kubernetes brings is a well-principled orchestration framework that can easily be extended with custom operators for workloads such as databases that need it. (In fairness, he does refer to this in passing at the end.)