Hardware sales numbers don't matter, profit does. And I'm guessing the WIi U is profitable for Nintendo when you have games like Smash and Mario Kart selling like they are, plus a few other million sellers. And I don't know about Vita games but Wii U has outstanding games so I doubt NIntendo would lose in quality there. Also what's with constantly comparing Wii U and Vita, compare handhelds to handhelds at least.
Edit: didn't mean to quote, just reply