Sony has a team dedicated to improving performance and working with third parties. ICE team or something like that. They've also been refining their low level ("close to the metal") drivers and API's or what have you while MS has only been talking theirs up ("close to the metal" coming soon with DX12!", while Sony has been fostering this heavily since the PS3 days and really strongly with the PS4) - which should be available on the X1 sometime later this year. In other words, on the console front, MS has been well behind for a long while.
I chalk it up to people not knowing the nuances of how these two companies have been working the past three or four years.