Why no Xbox?

[ReplicaX]

The problem is with Sony hands now, I think they don't want cross-play with Xbox because they can lose some console exclusivity like FFXIV.

Sorry, but no. It has been stated countless times in interviews with YoshiP that its MS not meeting SE requirements.

"Microsoft actually approached the Final Fantasy 14 team about the cross-platform opportunity," Yoshida told Polygon. "When our team reviewed the regulations that are associated with that, we realized that Microsoft may not have the experience or understanding of running an MMORPG as an online game genre just yet. The Final Fantasy 14 team has fed back to Microsoft that there are certain elements of its regulations that we would have to consider waived. We're waiting on Microsoft's response for that, but we are having discussions."

-YoshiP June 2016

One of the biggest roadblocks is having XBL on equal grounds with PSN. No paid platform membership aka PS+ isn't required. SE wants Gold membership waived.