If you have a co-worker with full copy of repository, isn't it already somewhat distributed? Of course it is not all attached to network.

The real problem that we should be talking about is - Pull request based workflow many companies (including mine) have adopted. Which doesn't work when github goes offline.

I hear from lot of teams, they have switched to using github issues for project managment entirely, so as pull request and tickets can be "seamlessly" linked. That goes out of window as well.