On topic with the last post on the front page, I think Microsoft's best move is to push in the same direction as Mozilla: web apps that are as good as native apps. Then your platform isn't the important thing.
Then why choose Windows (on your phone)? I think corporate workers would love for their work PC to just be the phone in their pocket. It should be x86-64 and run full-blown desktop application when a monitor, pointer and keyboard are attached. The latest Windows 10 Mobile is close, but it can't run any old x86 code. If my work PC was a Windows phone, I'd definitely find it easier to move in that direction in my personal life.
Web apps for the future, the occasional local app, and make the whole history of Windows on x86 a non-replicable asset for your platform.