Dolphin is a rare case where open source has benefited a project as delicate. Look at Pj64, it went open source and there is not a dream team that has improved emulation as rapidly. It is rare to find an open source so organized and goal orientated.
However, its was quite some time before N64 emulators went open source that popularity of the emulators dropped. Hard to say if there is a lot of interest in DreamCast emulation.
I coped the Project from 2 years ago to Github, so the source is available.
![Wink ;) ;)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
Just not the current version.
I cannot fully agree.
Dolphin organized itself over a very long period due to the open source characteristic.
They created automated tests, continuous integration, etc. because of the motivation of the different contributors.
Meanwhile a lot of developers are contributing to the project at github.
PJ64 is a bad example, due to political issues I would say.
Look at mupen64plus: based on mupen64 they created a opensource project in which several developers are now contributing to.
Meanwhile the git is very popular to requests features, to fix bugs or to enhance the code. Furthermore they are also trying to implement a CI approach now.
https://github.com/mupen64plus
Look at vba-m, yabause, mednaffen, pcsx-reloaded, pcsx2, retroarch etc.
They all benefit from opensource.
GlideN64 on github is also a very good example, which is on the on hand a very young project and on the other hand has already several contributors.
Coming back to DC Emulation: NullDC was the starting point for the Reicast team to enhance DC emulation.
Now this is also a very popular repository for developers too. Meanwhile the original NullDC code/emulation improved a lot.
The question is always how to attract developers for your project, and opensource would be the right step.