The "bait and switch" analogy is flawed. There has to be something to initially draw you to website and an element of plausible deniability. Say a banner ad on another website advertising fares "from" $300 to get you to the DL website, but then showing only $350 fares in a search. You don't know whether the $300 were already sold out, or were never there to begin with.

In this case, you went to the website on your volition and searched with no prior knowledge on what the fares would be. There's no point for DL to display the lower fares in the search if they actually want you to pay a higher price. What is the psychology that would cause you to pay the higher price when the search showed a lower price for the same flights? The reaction in the case of most people would be the exact same as yours. Rather than making you MORE likely to pay the higher price, it provokes the exact opposite reaction and makes you LESS likely to do so. If this was actually an intentional act, there's no plausible deniability and hence no purpose for it.

I certainly see how this is frustrating and one could be upset with DL for these inventory issues. However, I've seen the same thing happen with searches on Orbitz.