I'd say Pokemon fought its way back up with Pokemon B/W. But mainly the series is a simple RPG that is really addictive. I've played FF13 for instance and I don't really know why I find it so monotonous where as Pokemon doesn't really bore me out at all.

I think when they made R/B/Y, they really reached a very successful formula, and they didn't meddle with at all, which kept the formula intact. Many series lost that magic when it was meddled with too much like FF13, 2D platofrmers to 3D, etc... And as they say when it ain't broken don't fix it, and that's exactly how they managed to keep the game so addictive. Maybe during D/P it got a bit boring, but the last 2 Pokemon games were simply fantastic. I'm 22 and i actually got excited when B/W was announced like i was 8.

Simple exterior, with a deep metagame. Though granted Red/Blue certainly didn't have a deep meta so I'm not sure anymore.

Because of this:

http://youtu.be/-AlhaJF5Afw

ZOMFG, I had to stop watching it at 1:42, that was DISTURBING!  :-S