Patience is the key...those who want everything NOW will always end up paying a premium.
That's one way of thinking about it. Certainly in the nominal price paid, the premium is evident.
Conversely, those who buy it quickly don't incur the costs of 1) time spent endlessly searching through 1000's of eBay pages trying to get a better deal; 2) driving around looking for it at a flea store; 3) not having the satisfaction of having the module in your hands.
Incidentally, you also have some prices spike like the X7 you describe due to buyers looking to combine on shipping from the same seller, or local buyers who don't have to pay s/h.