The only question you need to ask yourself is, can XBO sell 2.3m more units than WiiU by the end of the year. If you think yes then the answer is by 2015.
With bigger brand name in america, microsoft's ad campaign, not out in the majority of the world which will give it another boost, exclusives like Halo, TitanFall, Kinect Sports, and Quantum Break (Possibly others unannounced either for 2014 or 2015), 2nd holiday with a likely $100 deal or pricecut, third party games such as Call of Duty, Witcher, Destiny, etc It is very possible that it will sell more than 2.3m than wiiu this year.
X looks great but it doesnt appeal to the masses. Neither does bayonetta. I honestly dont believe DKC is going to push much but it will have a boost during the holidays with a high attach rate (so will XBO, likely more considering $100 deal, halo, Quantum Break, KSR, and third party).
That leaves Mario Kart and Smash Bros to do the bulk of the work. Seeing as most Nintendo games sell well over lifetime rather than day one i dont see any reason to believe these two are going to push magical numbers within a few weeks either. They will have a big attach rate no doubt but considering the competition i dont know.
