Huh? WoW goods are key elements in a game specifically designed around their acquisition. IP is a tiny part of a completely different game we call the "economy," a game that was designed and refined around a radically different class of goods with essentially no attributes in common.
Trying to apply market-economic rules to IP is like trying to use a Zamboni as a lawnmower. Sure, it can be done, but you're going to have to force people to do it, and they are going to invent some very creative workarounds.
When you have to force people to follow the rules, it often means there's something wrong with the rules.
This is simply a difference of degree. If first-run movies were available to DVR off basic cable, they would also make far less money. In both cases, we discuss the economics of digital goods that derive value from an extrinsic scarcity.
