TL;DR if you open source a project prone to hype before you are established with a community, identity, and results to speak for, you risk entitled and uninformed users demanding more than you can deliver. Others may take your half-baked feature branches and release them (to fanfare from users who were able to use it with the exact one game it worked with), taking your credit.
Running these projects ain't easy and the Dolphin team deserves a lot of credit for doing it with a level of professionalism I'm sure many in here don't even see at work. The social work involved in this kind of project should not be taken for granted either.
Because some time ago I had multiple incompatible branches of Dolphin to support the games I played.
I'm not sure it was a half baked triforce fork but it was definitely not as polished as the main branch