Isn't this what they said about the 360 as well way back when? Probably wrong but hey.
Word is Microsoft wants to be on seperate servers entirely then the Playstation 3+4. However PS+PC are on same servers, so it would be a gated Xbox only community. I think they "could" do this technically, but in the long run I don't believe it's worth the time or effort, nor would it recoup the investment.