[derekp7]

If an airline seat could be sold profitably for 3 bucks, most consumers bought one or two seats a week, then the airlines could get away with probably charging 4 bucks for the same seat -- no one would blink an eye.

But when a seat costs $300, and people only purchase maybe once a year (or several years), then the airlines are less likely able to get away with charging $400.

In other words, two of the factors in this equation are how often the item is purchased, and how expensive it is (compared to the benefits).