Trent Reznor, (singer and songwriter) in Nine Inch Nails:
...when I asked a label rep about this his response was: "It's because we know you have a real core audience that will pay whatever it costs when you put something out - you know, true fans. It's the pop stuff we have to discount to get people to buy." So... I guess as a reward for being a "true fan" you get ripped off.
Treat your customers with respect by putting out some good, usable content at a decent price and they will treat you with that precious green stuff you love.