I doubt the average CE purchasers chooses not to open the box unless they're planning on reselling it for a higher price.
I think most view Collector's Edition as an enhanced gaming experience instead of something to be collected and displayed in a private museum. It's more akin to
"I'm such a fan of this game I want a box that has not just the game in it, but a ton of stuff related to the game as well. I'm literally looking to be showered in stuff from game-X because just having it running on my computer is not going to cut it.".
Now, I do have unopened CE boxes sitting on shelves for display purposes, but that's because I worked on them and they're more like trophies to define where years and years of my life have vanished to.
