Microsoft's XBox division and OS division are cannibalizing each other as I see it. And since Windows is paramount to Microsoft's overall sustainability, OS will always get the focus. They can try to sell both together as a strength but really, they are both competing for a gamer's attention. You can only play games on one at a time (for a single gamer obviously, I'm not including a family in this example).
There's no defining reason to own an XBox if you are also an avid PC gamer. Cross-play makes it even more noticeable. In fact, if you compare all of the gaming outlets (PC, PS4, XBOne, Nintendo), XBOne is the weakest out of all of them based on strengths. PC has everything and if you are willing to pay for high grade hardware, the sky is the limit. Sony has a variety of exclusives and majority support, Nintendo has the greatest (in number and in quality for some titles) exclusives but not much else. XBOne is kinda... there. Even its exclusives are mostly in a single genre, primarily FPSes. If you go with a primary/secondary console to give yourself the a bigger overall selection to choose from, pairing any with the XBOne is not a great option for diversity.