Will all children be using the wifi? No.
And isn't the main Japanese audience children?
You don't think there aren't early adapters in Japan who have been playing since Day One, as well. Pokemon isn't a fad in America anymore and while I would gather Pokemon is still rather profitable, lucrative, and iconic in Japanese culture, even in Tokyo, the popularity has slipped significantly since 1999, when it was a fad on both sides of the Pacific. Yes, I still think that the Pokemaniacs in Japan are generally adults who grew up on Pokemon, just as we did- although it may be more common in Japan for people who grew up with Pokemon in the 1990s to have children in 2013 now going through the same experiences they did when they were children in 1996. I would venture to guess that the stigma of being a "Pokemon-playing adult" does not exist in technology-crazed Japan, like it does in America. But yes, I feel that the majority of Pokemon trainers on both sides of the Pacific have been there since it started.