Which part of kubernetes is "developed with the intention to eventually get you to use the hosted version"?
Offering software for free, software that is widely adopted cannot be based on the motivations you propose, unless there is a grand conspiracy of cloud providers for which I am unaware.
It supports a standard OS environment and does not enforce the use of layers so users don't have to deal with single process non standard OS environment which removes half the complexity.
We are working on a project, Flockport, that supports LXC and provides an app store, orchestration, networking, distributed storage, service discovery and HA. So there are attempts to explore simpler alternatives.
I believe it's all of it. Why else would they spend money on building and promoting it?
For a huge number or organizations, the cloud isn't a meaningful option because the switching costs are astronomical. Kubernetes, otoh, means someone that chooses on prem today actually has a migration path later.
Google benefits hugely from that path just existing.