Ok, that's not really the same thing but either way, what's the point of having a decentralized project management system?
Code is one thing which clearly allows for many benefits in having the entire local history but pushes more work towards the merging stage. When it comes to issues and discussions, it's often much easier to have a single source of truth without worrying about merge conflicts.
And the issue with github being down isn't an issue of centralization as much as it is about availability of a service. You're free to use github enterprise or gitlab and host the service yourself if you feel you'll get better reliability and performance, however I'm pretty sure you won't beat github's overall without significant investment of time and resources.
Perhaps having a simple read-only offline cache of the latest project management state is a good middle-ground for most of the problem and it shouldn't be that hard to do - but again that's up to how much demand there really is for it.
