I regularly listen to the kubernetes podcast run by Google employees. Through time and through various guest interviews I've gotten the impression that some (most?) who created borg/kubernetes did basically all of the work that Docker did creating containers but are upset Docker has all that recognition. I can't quite articulate it but it seems like the Googlers are super judgmental and want to snub their noses at Docker.
The kernel is developed by Linux foundation and a variety of companies that have a vested interest in Linux like Intel, AMD, SUSE, RedHat, Google, Canonical. It's not a team of volunteers like it's popularly portrayed.
The foundation itself is also primarily funded by such companies.