Re: Could be a couple things...
Microsoft is hell-bent on making a go of Windows Phone, and also hell-bent on convincing PC users that they'd rather be using tablets with Store-curated apps
Really? The recent announcements about Office and Cortana for Android suggest that Nadella is winning the internal services over platform argument. There's a lot of money to be made from the Exchange solution on Android and IOS which is why Microsoft is going after it.