I'm not sure who's going to beat Docker. Docker is central to most orchestration tools so as long as they make money someplace with their central services, they should be fine.
Kubernetes could move to rkt or even the now standard systemd stuff, end users would hardly know the difference. The container format isn't a very strong lock-in effect and most people are probably better served without the image type format anyway (as the Linux block layer wasn't really constructed with that use case in mind, and fixing the plumbing will take longer time than developing the orchestration tools which is what'll win the users).
Docker the company have few options to monetize on Docker the software when it becomes commoditized. They seeminly chose the Enterprise way, which consists of pretty orchestration tools and integrations with Active Directory. (A perfectly valid option, which worked out well for VMware.) That's a dead end now that Kubernetes won container orchestration. It will be interesting to see where they will go next.
The kubernetes community is pouring a lot of resources into cri-o. I imagine you are going to see the kubernetes clusters that are built 'the hard way' start switching over and removing docker. It will still be used for building pushing containers for the time being.
Docker the company have few options to monetize on Docker the software when it becomes commoditized. They seeminly chose the Enterprise way, which consists of pretty orchestration tools and integrations with Active Directory. (A perfectly valid option, which worked out well for VMware.) That's a dead end now that Kubernetes won container orchestration. It will be interesting to see where they will go next.