Beating around the bush. It's obviously coming to the PS4.
There may be a deal that prevents them from saying "it's not a true exclusive" but there is no deal to prevent them from saying "the game is 100% exclusive to Xbone". It's actually beneficial for MS to just confirm the life-long exclusivity. So why not just do that? because it is timed exclusive
Looking forward to the release of the PS4/PS3 editions but not buying either.