By June 2016 it will be relevant.  Don't worry about me,  I'll get permission first.

I'm asking the question but your answer might very well turn out to be right! 

I'm going to side with "No".

I think I'm like a lot who assumed you meant mid 2015 :D
It's quite possible by then though I think it will be close regardless (barring any crazy price cuts/amazing bundles/etc etc that no one would foresee).

Imo if will happen by end of gen.
I See Wii U at 18m and XBO at 35m.
Stop with octimist prediction... /:

I think it's a tough call. X1 sod 3.5M more units in 2014 (doubling the Wii U). This years I think Wii U may end up down YOY, while X1 will probably be up YOY by a good amount, increasing the yearly gap.

I think the biggest challenge is that X1 would have only one holidays season in these timeframe to do it. Q1 2017 would be easier. But I wouldn't count X1 out of these fight, it can do it.

And thats why I asked this question.  a lot saying yes and a lot saying no.

Basics:
First six months of 2016, xb1 is easily capable of outselling by 50%. This past year was more than 1.7m to less than 1m
in the first 6 months.

So the question really is whether it can hit double wiiU numbers by year end +margin of a few hundred thousand units.
I don't see MS selling more than 12m this year (50% increase)...in fact I don't think they even have the production ability to sell that many.
But I also don't see wiiU selling less than 3m (25% decrease)
This would bring the totals to 23m vs 11.8

In the end though, the sign really is whether wiiU will have a price drop or not. Because with or without price drop on MS side, xb1 selling 12m is very doubtful...on top of which I don't think any console has ever increased by 50% in the second full year.

EDIT: So, this question really boils down to a question about whether wiiU will have a price drop or not. All the double sales talk is just filler. The bet will be over when Nintendo announces a price drop, probably coinciding with new handheld hardware announcement at e3, with presumably, the ability to interact with the wiiU.

You need a new calendar. Zelda pushes hardware, star fox and metroid also do. and no, wii u won't be down YOY.

just a reminder for your MK/smash thinking: they are out and their ltd should more than double in the next years = they will still sell systems while other games release.

Zelda pushes hardware, but the franchise's smaller than CoD and Fifa, that will be out on X1. Tomb Raider (and Uncharted) are basically the same size. Halo is much bigger and will push more hardware easily.

Star Fox topped 4M 3 gens ago and Metroid never topped 3M. Good numbers, but they wouldn't give that much of a push. How much hardware it pushes is related to how much software it sells. X1 has the advantage of hitting a massive 10-12M franchise against a 4-7M one in the holidays.