The revolution isn't in the technology. You're right; Docker is just a standardization of the use of these other components, for people to rally around. But the rallying-around is the revolutionary part. If everyone builds their own Docker, we can't interoperate at a "container" level. If everyone settles on one container format, we can.

In my opinion, Docker-the-implementation is only interesting insofar as it increases the network-effect of Docker-the-container-format. :)