The WiiU will be around till 2018 at the very least. The best year should be 2015 & 2016 when the system will retail for $249.99 or less.
2012 - 2.2 million
2013 - 3.2 million
2014 - current 900k - estimate for the year should be around 5 million
2015 - 7-8 million
2016 - 7-8 million
2017 - 5-7 million
2018 - 2-3 million
Last year WiiU's May, June, July and August sales were dreadful and they barely sold any consoles.
May-Aug 2013 sales were 426K ...... the WiiU sold 276K in May 2014 alone and Mario Kart is a game that can sustain sales for a long period of time.