I really just don't think they understand the tool, because any production environment should have many of the features Kubernetes helps provide. So the argument becomes "I know how to do it this other way, so learning a new tool is too complex."
Kubernetes helps standardize a lot of these things - I can very easily hop between different clusters running completely different apps/topologies and have a good sense of what's going on. A mish-mash of custom solutions re-inventing these wheels is, in my opinion, far more confusing.
> Kubernetes makes easy things harder than they should be, and hard things easier than they should be.
This is really the crux, I think. I think a lot of people look at Kubernetes, try to learn it by running their blog on a K8s platform, and decide it's overly complex to run something that Docker probably solves (alone) for them. When you need HA for many services, don't want to have to handle the hassle of your networking management, design your applications with clear abstractions, etc., and really need to start worrying about scale, Kubernetes starts to really shine.
/rant