Office and Windows boxes was its bread and butter. That needs to change. To do that change they have to expand beyond the Windows platform and as such work with Apple. Google and Kindle have the luxury have revenue from other sources and more importantly services. Microsoft was late to this game of subscription services. It had no choice but to hand over 30% of its revenue from each Office 360 subscription on the iOS. Tim Cook was very happy to hear that Microsoft Office for iPad is on the iPad. Apple will be taking its 30% cut.