All of the things you described as improvements are more complexity and layers of indirection. Kubernetes may be an attempt to improve on Borg but adding on a bunch of features and plugin architectures to solve more use cases isn't necessarily an improvement.
Kubernetes is actually the third system. In-between, there's Omega. Yegge must have never set up a GSLB or GFE service to appreciate the extra stuff that Kubernetes features.
