Where do you start....?
Why do people assume that a lost phone sale is lost forever, when most buyers are on two year contracts?
Despite it's runaway sales (at the cheap end), Android phones do not command the largest presence in web traffic and do not command the largest share in app sales. This tells me that outside the diehard fans, Android doesn't command that much brand loyalty.
Bold prediction time: I expect Microsoft to build market share in two year spurts.