Too be honest, the store owners really have no one to blame but themselves for noone buying their products. When they're selling booster boxes for $25-35 more than I can get it online, and singles at nearly double the price I can get them on troll and toad, ebay, or amazon, there is no way I am going to spend my money in their store, especially after spending money previous to the tournament to make sure I have all the cards I need for my deck, and then spending money on gas to get there. If they put fair prices on their product instead of trying to rip people off, I might support them more often.
And I say this as someone whose local league/tournaments are held at a community center and not a store. Not sure if I'm in the minority on this or not, but in general, I am more comfortable playing in a community center and being free to trade/sell cards freely, than being restricted from doing so in a store.
This isn't to say every store ridiculously marks up their product. Yeti in St. Louis for example, has some pretty good prices for booster packs. But for the most part, every card shop I've been to have had horrible prices...and yet they wonder why no one buys from their store.