Short article but it's hard to pull one quote from it.
http://venturebeat.com/2013/08/23/what-ballmer-did-for-xbox-and-what-his-retirement-means-for-its-future/
Microsoft has gone through huge changes in recent months. Mattrick always wanted to test the potential of the Xbox. He wanted to spin the division off as a separate company. But Ballmer as CEO wanted Microsoft to reap the rewards of an integrated Windows and Xbox company, fulfilling the long-held dream of a single operating system running across the office, home, mobile, and games. When the time for a reorganization happened, Ballmer chose to elevate Julie Larson-Green above Mattrick, putting a single leader in charge of Windows and Xbox. Mattrick left to take the CEO job at social-games publisher Zynga.
The reorg was consistent with the way that Microsoft designed the upcoming Xbox One: It has the Metro interface, it integrates other Microsoft products like Skype, and it has plenty of entertainment services beyond games. In other words, the Xbox One is about more than just games.
http://venturebeat.com/2013/08/23/what-ballmer-did-for-xbox-and-what-his-retirement-means-for-its-future/