I've been seeing this go down for the last three years and frankly, I think it might have been going on for a while before I even noticed.
The other day it dawned on me: the bubble has burst in the music industry.
Now, even to me this idea seems ludicrous, but look, it kind of makes sense: the costs of production have gone down in every segment (production and marketing), there is so much supply that frankly most of it isn't even that interesting. Promoters, bands and managers rely mostly on hype to get people excited about shows. It's always about the next great thing, when it actually should be about good music and musicianship (don't get me wrong - this trend is endemic to the music industry).
I agree with nearly every perspective above, it makes sense in one way or another. It's the end. It's been the end, the bubble burst more than three years ago. On one side, we're left with bands that chase a Brooklyn address because of the prestige such an association affords them. On the other, the people going to shows don't seem to be all that interested in the music. Frankly, Brooklyn has been taken over by the scenesters.