I don't think you can really relate wrestling to this situation.. it's a whole different dynamic. Wrestling has always been a boom-and-bust industry. Also, when the fans went away from wrestling, you're right that it was partly because of the novelty wearing off, but in many cases it's because the product itself worsened. I hate WWE TV shows these days because they focus too much on entertainment, and the little wrestling present is a lot worse nowdays. They push the wrong guys, and their storylines are just awful. It seems like they're desperately trying every week to get a high quarter-hour rating through shock value. Combine this all with horrifyingly distasteful skits and promos (JR surgery thing, exploiting Eddie for heat, etc) and it's a mess.
And, Brandogg, in fact, since they moved to USA, the ratings were dipping and after the Homecoming they were dangerously low. That's why you see the McMahons more and more (another thing I dislike). The past month the ratings increased because of Edge as the new champion, their "live sex scene", the main event TLC with Flair, and because it's fresh after Cena's reign.
So how the hell does this relate to games again? Hmm.. Oh right. OK, so as I was saying, fans go away if the product is bad. I think that if Nintendo can keep its consistent quality, the nongamers who have been attracted will stay. I also think that the nongamers will try out "gamer games" and they might be pulled in to enjoy traditional games. They bought a DS with Nintendogs or Brain Training or whatever. Now they have an expensive system with only one or two games. So they would be inclined to try out some of the other offerings, and they could get hooked. I know my dad (who plays rarely since the NES era) started off with the minigames in SM64DS, and he tried Kirby and loved it. He plays some of my traditional games quite a bit these days, and it's all thanks to the DS.