Well it's not the fans fault for not buying the game, it's the developers/publishers fault for churning out the same crap every year which it is, essentially, except for a few minor tweaks and changes here and there. However, Nintendo have been getting into this mind set with the NSMB series recently which I'm getting quite tired of now...
The problem is that publishers like Activision will churn out the same junk because they know it sells in the west like crazy. It really is crack to most people. So as soon as they get a bit of a dip in sales on a Nintendo platform it's all down to "Oh they prefer NSMBU compared to CoD..." well obviously, at least Nintendo try something new with their games. What have you done? Updated the graphics slightly, added some new crappier guns? Ah, right, okay... I'll just play NSMB.
It's not the consumer or the fans fault for not buying a game... it's all down to the industry churning out sequels and prequels and next instalments into a franchise than most people have gotten bored with years ago. Problem is, every developer and publisher is allergic to new IPs for some reason...