Earlier quoted context omitted.
It's too bad git requires a central server.
How is this a useful comment? Everybody knows that Git is distributed. Everytime Github's down, somebody feels the urge to remind everybody else about that. Github's not only Git. Lots of services integrate with Github. Stuff like continuous integration, continuous deployment. If your system is built on those things, Github being down will prevent you from deploying. What's the alternative, replicate everything in-ho…
Erm... Yes? You write that as if hosting your own repository is somehow a foolish or implausible thing to do.
Should startup stop using third party service providers?
Stop? Maybe, maybe not, it obviously depends on the circumstances.
Stop relying on them without a back-up plan? Absolutely. If you can't run your essential systems without GitHub, or any other third party system that isn't under your direct control, then you need better contingency planning.