"Two Simple Reasons We Overpay For Wedding Dresses"

Not really. Competition should drive the price to marginal cost no matter how ignorant or foolish the buyers are.

I suspect--but haven't checked--that a big part of the "overpayment" stems from the retail markup and that markup, in turn, has a lot to do with keeping a very large inventory that turns over slowly. 

Evidence seemingly in support: see bridal boutique Kleinfeld.