So i think there's a stark difference in what matters to fanboys vs. what matters to Xbox/Playstation. Fanboys seem to want to remain on a team where they can cuddle together and take turns licking their exclusive boxart. Xbox and Playstation are all about how to make the most money while still holding some semblance of a brand.
Thing is, since Playstation is more dominant, they hold more value in keeping their walled garden and branching out to PC so as not to diminish their brand by releasing their best games on Xbox. By the same token, Xbox is less dominant and so diminishing their brand is not as harmful. They instead choose to feed on the popularity of their rivals as well as PC and mobile to spread their net as wide as possible.
In the end, given the IP at Xbox's disposal, it is feasible that they would become dominant over time. They want their brand to be unbound the console space. Which makes sense because it is a battle they simply cannot win. But there are other ways to win, just gotta see if this pans out for them.
I predict Sony will follow suit...but still will not go to Xbox, because the benefit of going to Xbox does not outweigh the importance of maintaining the console space dominance. There isnt enough of an install base on Xbox to warrant a move like that. I think Sony eventually goes hard into mobile, drops VR, picks up handhelds again.