Before github there was sourceforge. It's pretty dead now but open source development continues.
So while I agree that an open and distributed system that does what github is currently doing would be better, I don't think that github's popularity and eventual demise is as terrible as you claim.
So while I agree that an open and distributed system that does what github is currently doing would be better, I don't think that github's popularity and eventual demise is as terrible as you claim.