How do you know my assumptions are wrong? have you got a crystal ball?

whenever you make predictions of this sort, just read this article: http://www.polygon.com/2014/5/15/5718168/mario-kart-series-sales

plus wii u has been on the market barely 2 years. it would have to be discontinued in 2016 for your 15m prediction to be correct. 2015 is its peak year in terms of first party releases and support. it won't be discontinued in 2016, it'll probably be around till at least 2017-8 (just going by 5-6 year cycle as the standard, which it tends to be). and that's assuming this isn't another long generation like the last. wii u is probably headed for 20-25m. nintendo could keep it on the market for years after the successor is released, as they did with the gamecube, just to prove a point.

Will sell more than Majoras Mask and Skyward Sword no doubt. Both those Zeldas were late gen games, when their respective consoles were on death's doorstep.

Zelda U will sell more since the Wii U is still fairly young in its lifecycle.

I say about 2mill first year and then about 5 mill life time.

It's so sad that THIS Zelda is releasing o Nintendo's worst selling console, it will severely hamper the potential sales. This could be one of THE best Zelda games made, but considering the Wii U install base, I think we should be happy if the game sells 4m.