A glut of lobster in the ocean has driven its wholesale price down, yet restaurants have kept lobster dishes on the menu at historical high price points. James Surowiecki explains the many reasons why, including this:

Lobster hasn’t always been a high-end product. In Colonial New England, it was a low-class food, in part because it was so abundant: servants, as a condition of their employment, insisted on not being fed lobster more than three times a week. In the nineteenth century, it became generally popular, but then, as overharvesting depleted supplies, it got to be associated with the wealthy (who could afford it). In the process, high prices became an important part of lobster’s image. And, as with many luxury goods, expense is closely linked to enjoyment. Studies have shown that people prefer inexpensive wines in blind taste tests, but that they actually get more pleasure from drinking wine they are told is expensive. If lobster were priced like chicken, we might enjoy it less.

Restaurants also worry about the message that discounting sends. Studies dating back to the nineteen-forties show that when people can’t objectively evaluate a product before they buy it (as is the case with a meal) they often assume a correlation between price and quality. Since most customers don’t know what’s been happening to the wholesale price of lobster, cutting the price could send the wrong signal: people might think your lobster is inferior to that of your competitors. A 1996 study found that restaurants wouldn’t place more orders with wholesalers even if lobster prices fell twenty-five per cent. As the study’s authors put it, “A low price creates suspicion.” This helps explain one of the interesting strategies that restaurants have adopted to take advantage of the lower price for lobster: they keep the price of lobster entrées high, but add lower-priced items—lobster bisque, lobster mac-and-cheese, a lobster B.L.T—to the menu. That way, they can generate more business without endangering lobster’s exclusive image.

I wonder if lobster prices remain high at seafood markets, or even Costco. They don't have to engage is menu price portfolio construction, but the perceptual illusion that higher priced lobster tastes better still exists.