That's a good question, and the mobile market is cutthroat when even companies like HTC/Samsung/Lenovo etc is struggling to survive. However I think Microsoft

That's a good question, and the mobile market is cutthroat when even companies like HTC/Samsung/Lenovo etc is struggling to survive. However I think Microsoft has a lot of synergy good both on the gaming side with Xbox and on the business side with Office/Sharepoint/Outlook etc, not to mention that Windows still is the most popular OS. Now I tend to agree with Nadella's "be everywhere"-strategy but that doesn't mean they can put everything into Microsoft services and software being the best on their own devices. I think the fact they're doing xbox games that are free to use on PC's is a good example of such synergy. In the end selling hardware is never going to be what they earn money on, but rather they need to be a hardware actor so that they profit off their app store/software/services.