Thank a couple of Ph.D.'s a decade or two ago who invented revenue management and then those who created a computer model to implement it -- although the airlines don't trust the computer model and have significant revenue management staff who tinker with its output continuously. Despite that, most airlines follow this model religiously.

That means that the airline ticket market is not a free and open market. Broadway theatres get little or minimal revenue once you're in the theatre. But last minute Broadway theatre tickets can either be sky high or dirt cheap: it depends on the day, time, and the demand for that particular show. In a free and open market, the same would be true for last minute airline tickets.