I feel like the only thing that can save Fx at this point is a community-funded, community-led fork. The only problem is: this project would need a lot of monies, so unless there's a corporate sponsor (or sponsors) it's unlikely to happen. And corporate sponsorship would require some sort of incentive that makes the investment worthwhile but at the same it it can't compromise the spirit of the project.

Let's say that the cost of a single full time contributor is $200k/y on average. Every 10 people working on the project cost $2mil/year - that's roughly the funds FreeBSD raises each year (and 3-4x more OpenBSD does). And I don't think you can continue independent fork with 10 people; you'd need 30-50 for the fork to make sense. I suspect it would be possible to get corporate sponsorship for the infrastructure needed so I'm not counting those costs but at this scale there's some legal and administrative overhead that has to be taken into account as well.

So the bottom line seems to be that you need around $10mil per year to let Fx survive as a community project. And I'm pretty sure you can't crowdfund that much. :S