They're all-in on Kubernetes, which is quite apparent given (a) who's funding them and (b) product direction, including this one. They don't have the resources

They're all-in on Kubernetes, which is quite apparent given (a) who's funding them and (b) product direction, including this one. They don't have the resources or backing to go after Docker; notice that changed? Docker has something like 15x the funding and is pulling away in a lot of ways, so CoreOS hitched on the Kubernetes wagon. Better bet for destiny: Google is letting them build stuff off the books by just funding them, and at some point they'll get quietly bought with all their stuff added to Kubernetes, and that'll be that.