Well, the drop in attendance at museums could easily be explained by individuals' infatuation with the Internet as a substitute (for the museum) learning experience. Besides, are we being 'museummed' to death, ie, there's just too many museums these days. Museum ad-naseum.
Disney World's attendance decline might likely be due to the aggravations involved with air travel these days. Admittedly, said aggravations are likely due to 9/11, but FEW of FRFF attendees require air transport.
Given the 'touchy-feely' character of folk music (festivals), I'd be inclined to think that that quality might result in increased attendance.