I was all in on windows mobile around v7 and windows8. bought the flagship lumia phone and surface rt tablet. invested the time to develop some basic apps. 6 months later both platforms were basically discontinued with no upgrade path, so I abandoned it too.
if microsoft had just made an enterprise successor to blackberry, instead of trying to make a consumer phone, they probably would have been more successful. once the platform had traction in enterprise, maybe they could of made the consumer jump.