What's your alternative here?

I mean...it works just fine without internet...host your own registry...or just build your own from Dockerfiles locally. Not saying it is the right use case for everything but I'm confused what you mean by docker doesn't work without the internet. Neither does pip, rubygems, apt, etc...unless you build locally or host your own repository. Can you elaborate on what exactly you mean because you probably have a point that I am just missing.

You can also docker save + docker load :)