Nokia execs should ask themselves this: As the pioneer of PC market, why IBM doesn't have any product in the PC market today?

This is the same situation. MS will create an 'ecosystem' with the help of Nokia. And then cheaper products from Asia will take over that ecosystem. It doesn't matter for Microsoft who licenses their OS after all. In the end MS will have a great share of mobile OSes but Nokia will be long forgotten. IBM had the chance to return mainframe computer business but Nokia doesn't even have that.