When I'm talking about project sustainability, I'm talking about more than developers by the way.
I don't code in C which at the moment is what @librecast is written in. But I still contribute time, with grant applications, reporting, managing the project account, community etc.
This isn't directly funded. It's a similar story for folks in other projects who give that support, their time for gratis. What happens when their cash runs out, the project loses.