I listened to that story about the black and white Gameboy version of Rampart. Yes, the price seems to have gone down now, but it doesn't change the fact that one single seller was able to single handedly increase the price on the ebay market. Ebay being ebay, prices don't exactly revert to the same rate that it was before this guy's experiment very quickly. It seems like as soon as a price reaches a new ceiling, every seller assumes that new high price is the actual price point. One idiot buys something at a high price and afterward nobody well sell for less.
Even as the ebay price falls, there are still long standing ramifications to this in other locations. Recently I saw a copy in a retro game store with a price tag of $35. That game at that price is absolutely ridiculous. No, I don't think that it will Ever sell for that much but at the very least I feel this is strong (albeit nonscientific and a bit anecdotal) evidence that one profiteering jerk can create an artificial scarcity on his own to influence the market for monopolistic price fixing purposes which would never be legal on a large scale.