I doubt FPS will ever die out (at least foreseeable future). Reasons for me are as follows:
1) Online - next to MMO's no other genre comes close online so far as I can see and people just love the competition element of playing FPS online
2) Immersion - our primary sense is sight. No other gaming perspective is as immerse as FPS. You're there. Looking around. Now I'd argue you don't always have to be shooting but that perspective is never going to get old for many people as its so natural
3) Flexibility - while there are too many copycat FPS - it's also one of the most versatile genres, particularly online. Look at Portal, look at Left 4 Dead. Look at Mirror's Edge. Anything that works as an action game could be FPS.
4) Action Film - FPS link. People love action films. And many love feeling like they're in one playing an FPS. I don't see this changing anytime soon.
Now not everyone likes FPS which is fair enough. But I really doubt the genre is going anywhere anytime soon.
Try to be reasonable... its easier than you think...
