Or we could invent better solutions where we didn't need to depend on policies imposed by vendors? The value that Github provides isn't around their git hosting

Or we could invent better solutions where we didn't need to depend on policies imposed by vendors? The value that Github provides isn't around their git hosting, it's all the integrated features. Reimplementing that isn't going to be trivial - there's a reason so many people use hosted Git rather than doing it themselves.