I look at that article as more of an advertisement in disguise. I believe in there the guy states that the information is based on how many people take advantage of their trade in opportunity. So to me it is less about people not understanding you can do it, and more about they have dropped their trade in values so far people are going elsewhere to trade their games in. If they want to reinvigorate that business they have to go back to the way it was 10 years ago or so and make it worth someone's while to trade a game in.
For instance, last week I gave them a chance to match Best Buy's trade in. Gamestop offered me $7, and I got $35 from Best Buy. So it is more about their lack of keeping pace with the competition than their customer's ignorance.