"Remember the Kin?"
The fact that someone at Microsoft believed they could sell the Kin in 2010 it is a clear sign they didn't get a clue about the mobile phone market - and the acquisition of Danger were really money thrown away. It looks the Zune failure never taught them anything.
With Nokia they had a chance to deliver a real mobile platform, but it was late and it would have required a multi-year effort and commitment. something someone like Nadella isn't strong enough to attempt - he just hopes to make money from the cloud while trying to limit damages elsewhere, he's a follower without a vision.