Well im just glad that VGChartz was able to get their sales back up and going, we probably still back in September by now. But since Sony doesn't give us Vita sales, we have Vgchartz to rely on. 

And same thing goes to the PS4 and the Wii U. I'll be surprised if anyone is surprised how the PS4 is slaying the Wii U =D 

It's because it's not financially worth it for MS. PS4 was already estimated to be slightly cheaper to manufacture than a Kinectless Xbox One from the get go. And the more you sell, the faster the cost of the parts will go down. Obviously Sony has been selling more worldwide from day 1. When Microsoft unbundled the Kinect, that also lost them money due to the projections they had for the device and the deals they had made with manufacturers based on those projections. Later in the year, MS had a price cut and some crazy deals during the holidays such as getting an XB1 for the value of $150, if you also buy 5 games. In spite of XB1 being more expensive to make than PS4. MS made these investments because they hoped it would pay off in the long run. Early adopters are more likely to buy more games than late adopters, and if XB1 was able to dominate the US, it would give them more momentum. (People play on the console their friends are playing on, etc.)

It's now come to the point where they have to look at how much they've spent to try to beat Sony in the US, and what that has given them. If they have to spend X amount of dollars more to be ahead of Sony by 200k units in lifetime sales in the US, and keep doing that every year, will it be worth it?
They had Halo 5 and Tomb Raider exclusively on their platyform this holiday, while Sony had no particular exclusives besides an Uncharted Remake. And it still wasn't enough.
At that point, investors and management alike will be more interested in being profitable than keep fighting a losing battle where they have to put in a lot more effort (money) than the opposition just to do that much.