The problem for Xb one is that the Gears bundle is staying at 10-12 level and not replacing the SWBF bundle at 1-3. So it's sales are not jumping up as a consequence of PS4 dropping back. They are just holding steady while PS4 fluctuates.
“The fundamental cause of the trouble is that in the modern world the stupid are cocksure while the intelligent are full of doubt.” - Bertrand Russell
"When the power of love overcomes the love of power, the world will know peace."
Jimi Hendrix