The X4 and X6 are both niche styling exercises, but so is the Evoque. And for some reason I know many, many people who are way more attracted to that car than the X4. Hell, I awarded the win of this test to the X4 based on logic, but I find myself lusting more for the Evoque too based on looks alone!
I think styling is a valid reason to buy (and even build) a car.
My hunch is BMW have hit the targets they expected/wanted with the X6.