I saw this old article from 2008 and the comment made by GameWiz1 is right on the mark on what this whole thread discussion is about. The author doesn't even mention the loss of trade-in value of disc versus DLC, but the gamer comment does. Smart guy. He stated:
"The only thing I'm interested in seeing is if they lower the (DLC) price enough to where it doesn't matter that I can't take the game to gamestop for a trade. If they don't have to go through all the steps of shipping, packaging, and all those little things that are required to sell a game, then I don't see why those games aren't currently selling for somewhere around twenty to thirty dollars tops."