...Maybe that's because the developers know a highly rated FPS will sell good, so they make them more often?
It's supply side economics: you make what sells. The problem is that developers haven't noticed that the X360 is trying to break out of the FPS/TPS mold and go into other things. Sports games, for example, have done very very well on the X360 - far better than they did on the Xbox.
It's just a matter of time that the userbase broadens more and more, forcing developers to notice that other games do well. RTSes are also becoming more and more regular on the 360. Also, the fact is, the X360 is very PC-heavy in userbase, and producer base. Because of this, we can see the genres that mirror PC games very easily (sans sim games).
Back from the dead, I'm afraid.
