I think that there are a lot of factors. Economics plays a huge part. "Discretionary" funds are tough for people to find, taking a week off to go to Friendship or a Rendezvous isn't as easy as it was in the 90's for many folks. The average age of participants is getting older, and on and on. The hobby itself has also seemed to have peaked, attendance has stabilized, or even fallen off, at all but some of the more noteworthy events, and the huge influx of new people we saw in the 80's and 90's has ended. A lot of the tire-kickers have left, both shooters and reenactors.
To be sure, there are things which could have been handled a lot better! An argument that I have been having for 20 years is that the Association, despite it's giving lip service to the fact, is far from a truly "National" organization. There is a centrist sort of mentality that places a lot of the importance strictly on Friendship itself, and those who have geography on their side can take advantage of it. Oh, sure, when a bunch of the old timers went West, the Ben Avery Range setup came into being. But the shooting aspect of the hobby on a National level really was hurt, IMHO, by the loss of the old Levi Garrett Territorial programs, the monthly shoot reports in the magazine from charter clubs, all the things that got the Ass'n out into OUR neighborhoods, not theirs! I cringe when I see the costs incurred to keep the site at Friendship going, when every report I hear is that attendance is WAY down.
Bottom line is that the membership is about half of what I recall it being in the 90's. Mismanagement, to a degree, yes. Changing times, also a factor. Whatever the reason, adjustments have to be made, especially in the way the money gets spent. Capital improvements at Friendship should really take a back burner. I don't think that there has been any significant reduction in staffing and operational costs (some of which are fixed, like taxes, etc,) and elimination of incurring new debt has been addressed, at least where I have seen it, until the membership levels and income are figured out. One thing's for certain, those levels are not going to be the same as they were back in the day!
But having said all that, beside the NRA, who seems perfectly willing to give away my black plastic guns, there really isn't a viable organization of any sort for BP shooters other than the Ass'n., and despite it's flaws, which are many, I still think that an established forum available to those of us who shoot or reenact is worth a double sawbuck or so when I can find one to spare. I have a lot easier time swallowing the cost of membership (and the book, which does have it's redeeming qualities) than I do the horrific fees I pay every day for my insurance, gas, diesel fuel, etc.. The Ass'n. may be crappy, but it's CHEAP crappy compared to the rest, and it's something I get to choose to spend, on something I like to do, not arbitrarily taken from me.