Another thing to point out-
Yes, many expensive games are priced high because they are desirable. Take Addams family for example. Everyone loves that game. However, everyone has also played it and is very familiar with it. I don't understand investing in something I can play everywhere!
Look at my collection.
I have 1 game in the top 100, and its pretty high up there. It's usually around the top 70-90. All of my other pins are unique. I bought them because I couldn't play them anywhere and they fit my interests. I constantly have people saying "Oh my gosh, you have a Bone Busters! That's awesome!" Or "Can I come over to play Hook?"
Neither of those games are spectacular, but people don't see them often, so my collection is unique, and they both cost less than half of most top 100 games.