I have to disagree with you
Your privilege.
FYI, I don't have any secret knowledge on MS Plans. I have been working with Microsoft for years. I have partnered with MS for many years. I have many friends who I have worked with over 20+ years that work for Microsoft.
Here are a few ways to see what is important to Microsoft. First check the session content for the MS Build Conference. If MS was getting into any of the areas you list they would need developer support. If you check the last Build conference you will see no sessions on any phones or pocketable devices. You can also check on what is scheduled for the MS Ignite Conference in November. Almost all of the content is about Microsoft's cloud offerings - Azure and Office 365. The mobile classes focus on MS services running on Android and iOS.
Second, watch what Microsoft is communicating to their development and business partners. The communication would have started at least six months ago. Any big news will have started to leak out.
If Microsoft was getting back into the mobile space, developers would have been told long ago. Microsoft would have to rebuild relationships with the major phone carriers. Analysts and the press would have been briefed. You would have planned and unplanned leaks all over the place.
The next big new hardware announcement from MS will be about Centaurus. The current word on the street is the MS will not announce Centaurus on Oct. 2nd. This might change or maybe the hold Centarus for the Ignite conference. Will depend on how close the Microsoft is in releasing Windows Core OS.