Two problems with the wii comparison. One, handhelds aren't consoles and the past couple gens show some huge legs to them, probably more to do with competition, price, and expectations. Two, it's doing better than the wii.
As for the vita in Japan highly doubt it matters. Eveyone has both a ds and a psp there. Hell, the psp ain't that far from the gba thanks to them.
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The King Wang.
Listen up Urinal Cake. I already have something that tells me if I'm too drunk when I pee on it: My friends. - Colbert.