This Microsoft notion of “devices that don’t stand alone but surround you” sounds an awful lot like Google’s “ambient computing” of yonder.
With the right set-top-box, you tvs become just another display for whatever you want to send their way. We are extremely close to startrek tng style spaces. I'm sure there is a github repo out there that may even be there.
Why do you think apple has the appletv, the apple watch, the phone itself is essentially a pocketwatch with an addressable display.
I think we have all the parts it's just now about knitting them all together and building up a ux that works for normal people.