What is distributed here? If github is down no one can see what you changed, not even the build servers. Git is distributed in the sense that every client has complete history, but not in the sense that my laptop can act as replacement of github(like torrent).
Git is distributed in the sense that you have a copy of the source code and can make commits. Compare this to what would happen if an SVN server went down.
Even in SVN there is a copy of the current code everywhere. Just that it does not support having multiple repos and all which I don't think many people uses in git. Most orgs only have one remote repo setup(I would love to be wrong in this)
I wish I could agree with you - still, these outages just reveal that GitHub is much more important to software development than pushing changes into a git repository.
the fact that git is distributed is but a small part of the whole.