GitHub is not Git! The latter is just an engine, but GitHub goes far beyond that.
It is very disappointing to see so many posts in this thread, touting Git as an alternative.
GitHub is just a Git hosting service. What are you doing when working with GitHub? You're actually working with Git, and pushing to GitHub.
It is the technical sub of the bloody original bitcoin forum, we are all supposed to avoid spreading misinformation.
Github is a web application that uses Git, the latter is a Version Control System, CVS. When you work with Github you are offered dozens of features and utilities that are not part of a CVS.
Git is open source and free, while Github is a multibillion $ property of Microsoft that provides a sophisticated user interface for versioning, it is not hosting in the exact sense of the word. Hosts are infrastructure providers, they host your own or third party software for you.
Github doesn't abstract users from Git, because typically the user is a software engineer/programmer, the one who abstracts but doesn't like to be abstracted8), it is a matter of design and requirements.
As much as it is needed, it is hard to replace Github, but not impossible. The alternative is neither bare Git, nor another Github-like centralized service. What we need ( and it is inevitable, imo), is a decentralized network of Git repositories behind a decentralized web application.
There are decent technologies that are available, and as I mentioned above thread I've done some research about it years ago, only missing factors, as usual, money and commitment.