The organizers finally went ahead and officially admitted that they've cancelled Alt-Fest: http://www.alt-fest.com/index.html
Considering that they waited to make this announcement until after 4 out of 6 headliners, countless other bands, a couple of vendors, and the bus company that was running transportation to the site had announced that it was off, it didn't exactly come as a surprise.
Basically, the organizers underestimated the cost and overestimated the ticket sales. The latter surprised me a bit, since I'd have thought that the quality of the lineup would have drawn more people. Perhaps many of those people decided to wait until the organizers demonstrated that they could pull this off. Wisely, as it turned out.
I am a bit peeved about the amount of b.s. the organizers put out about ticket sales during the lead up to the festival. While it's clearly not in their interests to publicize poor ticket sales, they did quite a bit to give the impression that sales were brisk, even claiming at one point within the past month that there were "fewer than 900 tickets left".
Ah, well. We live, we learn, we plan birthday hijinx in London, and we hope against hope that Fields of the Nephilim will tour the U.S. someday.