Yeah... there are a lot of other "damn good game(s)" that can be had for a 1/5th of the price. Good game doesn't = mega price.
What does dictate price is demand. $5,500 is fine if the demand is there. All you have to do is look at sales history to have a good idea of what will call out the buyers.
All that being said, seller can ask whatever he wants. $5,500 OBO is totally reasonable. If you desperate want the game, you have a good idea of what it will take to get it!