Sane defaults is in conflict with "turning you into a customer of cloud provider managed services".
The longer I look at k8s, the more I see it "batteries not included" around storage, networking, etc, with the result being that the batteries come with a bill attached from AWS, GCP, etc. K8s is less of an open source project, and more as a way encourage dependency on these extremely lucrative gap filler services from the cloud providers.
Except you can easily install calico, istio, and ceph on used hardware in your garage and get an experience nearly identical to every hyper scaler using entirely free open source software.
Having worked on on-prem K8s deployments, yes, you can do this. But getting it to production grade is very different than a garage-quality proof of concept.
I think OP's point was: but how much of that production grade woe is the fault of Kubernetes versus, sure, turns out booting up an PaaS from scratch is hard as nails. I think that k8s pluggable design also blurs that boundary in most people's heads. I can't think of the last time the control plane shit itself, versus everyone and their cousin has a CLBO story for the component controllers installed on top of k8s
You could have sane defaults for something running locally. Take Jenkins as example, all you do is start it up and give your agents an SSH key. That's it, you get a distributed execution environment. Not saying Jenkins does what K8s does, but from an operational standpoint, it shouldn't have to be much different.
I invite anyone to try reading https://kubernetes.io/docs/setup/production-environment/. It starts with "there are many options". Inside every option there are even more options and considerations, half of which nobody cares about. Why would i ever care which container runtime or network stack that is used. It's unnecessary complexity. Those are edge cases, give something sane out of the box.
The longer I look at k8s, the more I see it "batteries not included" around storage, networking, etc, with the result being that the batteries come with a bill attached from AWS, GCP, etc. K8s is less of an open source project, and more as a way encourage dependency on these extremely lucrative gap filler services from the cloud providers.