He was a business division president not the CEO. Ballmer is the CEO. Actually, iirc, he was the business division president for Office, so he didn't even have

He was a business division president not the CEO. Ballmer is the CEO. Actually, iirc, he was the business division president for Office, so he didn't even have a history with the phone division. I suspect his move was due less to some undying loyalty to Microsoft and more to him deciding it was his best option (one may disagree, but we also aren't aware of the other options/limitations/incentives in place when the decision was made, so we are just arm-chair quarterbacking).