We have a tendency to forget that most folks who keep reef tanks aren't involved in the local clubs. There aren't enough active club members to keep one LFS alive, let alone a dozen in the metro area. We have a very active group of critter keepers, but we actually represent a small (some might venture 'crazed') section of the market.
We pull folks from the fliers at LFS, Craigslist, word of mouth, vendor advertisements, magazine ads and other sources.... such as ReefBuilders.com and FB.
Yep... we depend on the local club community.... but I would venture that I had never seen 1/4 of the folks who showed up, if not more. I'd lay odds that if you randomly approached someone, half of them could name one of the clubs, but most of them couldn't tell you when the last or next meeting was.
And don't get me wrong.... it's not a complaint or a negative... it's just the market. Lot's of folks have aquariums, but few of them actually join a club. Of those who join a club, even fewer of them are active on a regular basis.
Ask your favorite LFS how many of their customers are active members of a club... you might be surprised at their answer.