Ballmer was CEO for over 14 years, during which very little of this happened. While some of this was obviously being worked on under him, I find it hard to buy

Ballmer was CEO for over 14 years, during which very little of this happened. While some of this was obviously being worked on under him, I find it hard to buy the idea that Ballmer did all the work and Nadella just swooped in and took the credit.