He stopped working on it because he felt it was dead end to keep supporting it since vim plugins are so hacky, but the community loves his plugin. It's has a massive number of forks and patches but he hasn't touched it since 2009.
This fork has taken up most of the new development on the project and really has pushed it hard to almost a 1.0 now: https://github.com/garbas/vim-snipmate
Couldn't he have given someone permission to take over the original repo via pull requests? I was working on a ruby web app with a guy from Italy and the project is dead but I gave him access to the repo and now he can commit and push all he likes until I get the time to work on it again. Would that work for your friend? Maybe he could appoint someone to take charge of that particular repo and keep the original project alive without giving him access to the whole account.
Edit: after reading some other comments I'd also like to suggest that creating an organization would help. Once the project is abandoned by the creator someone else can take over and the creator just drops off. Of course this only works if people put it into practice but it can possibly mitigate some of the problems you have.
If people would be thinking of these things and put these solutions into practice then your criticisms would be a little less necessary. But alas, you can't always rely on people. It really comes down to a choice the way I see it. The way things are and the way you wish they were both have merit. What if GitHub just supported viewing forks differently? It would be cool to see a list of forks without a master for some and a hierarchy for others depending on how you want to filter the page. That would be cool and do a bit of good.
The one case I didn't link but talked about was my co-worker Michael's snipmate.vim project.
https://github.com/msanders/snipmate.vim
He stopped working on it because he felt it was dead end to keep supporting it since vim plugins are so hacky, but the community loves his plugin. It's has a massive number of forks and patches but he hasn't touched it since 2009.
This fork has taken up most of the new development on the project and really has pushed it hard to almost a 1.0 now: https://github.com/garbas/vim-snipmate