I suppose that makes sense.
Not every game gets updated to support the PS4 Pro, or Microsoft’s super powered Xbox One X; one of the games that didn’t is Tekken 7, even though it did get enhanced for Sony’s console. The reason for that, as it turns out, is that the Xbox One X, with a significant amount of new hardware, would require a more through retooling of the game.
Katsuhiro Harada, game director and producer on the Tekken series, talked about the possibility of an Xbox One X patch on Twitter, noting that the sheer amount and type of new hardware on the Xbox One X would require changes in the game’s memory structure, among other things, to enable it for native 4K on the Xbox One X (which he also says is achievable).
Beyond that, we don’t get any concrete indication of whether or not they will do it, but if it does not end up happening, at least fans now know why.
The spec is enough (Of course TEKKEN7 is 4K compatible with Steam).
But It requires a significant update of Unreal (UE version of TK7) for X.
With the new hardware, we've to change the way access our memory greatly
RT @Taskmaster90 why was Tekken7 4K too hard to make for Xbox X?
— Katsuhiro Harada (@Harada_TEKKEN) February 16, 2018