The problem with the hunt, (and your theory) is that as time goes on, the rarer games get more and more expensive, and the longer you hunt, the more expensive they get, especially in the open market, and the more people become aware that they're worth a lot, the more people you end up with in the hunt...
I suppose I could wait year after year, garage sale hunting, forum searching, etc... but I don't enjoy scavenger hunting, I have a day job, I have 3 kids, and a wife. For me, the hunt is just a PITA. :-)
My feeling is that with a lot of these games, good deals are going to get fewer and farther in-between, and a good forum deal a year from now may very well be what I can get it for on ebay today.