Which will then grow again for the next 48 weeks, with or without retaining the price at 349.

My apologies lol. Humbled I shall be!

Agreed.  Much like these holidays the next holidays will do the same especially with Halo 5. This is a given I think.

Currently the ps4 is over the x1 by 700k in the US. Gap was closed by 80k this week to reaach 700k. They won't even win US by this xmas, and then ps4 is going to gain so much ground in the next 9 months that x1 isn't going to be able to come back. If x1 goes back to 399 in Jan, that's the end of the race. Say hello to <30k average weekly sales US.

Pretty much this.

xb1 will win the us. no matter of the excat selling price.
it is always a bunch of reasons, for consumer to chose one product over another.

there is so much possible until the end of this nex generation


xb1 cut the ps4 lead by about 1/3 this november.
december sales gap in favour of xb1 could be even higher, or just slightly lower
january could be a win by a low margin, too. this januaray there are way less scalper, who will return unsold xb1s. januaray buyer demographics could favour xbox one. kids who used theire christmas money to buy the console of choice.

i don't want to look at febuary right now. could go either way and it will heavily depend on what kind of deals and bundles ms and sony will offer. but sony get at least one exclusive game.

If there are always a bunch of reasons for cunsumers to chose one product over the other then how can you say the XB1 will win the US basically no matter what? I mean you say no matter the exact selling price but at the same price the XB1 could not outsell the PS4 at all so you can't say no matter the exact selling price. What makes you say that the XB1 will win the US for sure? The December gap is already way samller than the Nov gap there was almost no week in the month of Nov where the XB1 did not basically double the PS4 in sales except for the BF week. And this week it is only ahead by 80k were the XB1 sales have fallen but the PS4 sales are pretty steady.  So the December sales gap will be significantly lower IMO.

And if you are using kids who use their Christmas money to buy the console of choice then wouldn't that be the PS4? What makes it the XB1? And sorry but unless MS keeps the current price point then they won't win Feb at all and if the price point does end Jan 3rd they definitely won't win Jan.

There's only one reason American's will need in 2015 to buy an Xbox One and that's Halo 5.

But that doesn't come until the holiday what about the rest of the year? Don't get me wrong I am not saying there is no reason to get an XB1 because there are plenty IMO and surprisingly Halo is not one fo them! But in 2015 if Halo 5 is the ONLY ONE REASON as you put it for Americans(even though I am an American and will not be getting it so it kind of makes your point moot lol) to get an XB1 then it will be a LONG year for the XB1 seeing as it doesn't come out until the fall/holiday season. And it will have some HEAVY competition in Uncharted 4 which is rumored to release around the same time.

So yeah it will need more than Halo 5 if you ask me...a Gears collection would be AWESOME and maybe Lost Odyssey 2 to go along with QB! That would be GREAT!!!

IF X1 maintain the price difference on the more expensive to produce PS4 they can win the US.

OP does not mention the two major change that Microsoft has done to compete against PS4:

1st: They removed the Kinect from the bundles.

2nd: X1 was selling for more then PS4 up to June 2014. Microsoft can maintain this price difference since the Xbox One cost less then PS4 to Manufacturer due to cheaper components.