marketshare wise in the US X1 is 45 % while PS4 is 55 % (between PS4 and X1 only, not including Wii U)
This is still extremely close and the price cut will definitely recover X1 sales in the USA.
That's not close. Percentages are scalar quantities, not definitive quantities.
For instance, Sony sells 55 PS4's and MS sells 45 X1's. That's close because that's only a 10 unit difference.
However, the sales figures are much larger and the gap is 600-700k. That isn't small. As said before, your original 10k per week (and after that, 15k per week) prediction is totally false. The X1 needs to outsell the PS4 by 21500 to 25000 units per week, more than twice your original "prediction". To outsell the PS4 each week by that much is impossible. Why? As we seen from multiplats like Tomb Raider, MGS: Ground Zeroes, Wolfenstein, and Watch Dogs, they move more PS4's than X1's. Because Sony has exclusive advertising rights to Destiny, more people will be inclined to buy PS4's.