Man, I have a 4K TV and a whole LOT of 4K movies,. but damn no 4K players. I don't think I will even go buy a separate 4K player if Video Games systems like Xbox, PS4, Nintendo supports it.
However, I know PS4 even Pro doesn't have a 4K player, which I still don't understand. Also Nintendo switch don't either I am pretty sure. So, just Xbox does, and I am not one to buy a older version of Xbox One S, when X is out. Cuz, the performance and graphics quality will look better on One X rather than S, I believe.
I would buy a Xbox One X, eventually, but not without a price drop. Or at least a Limited/Collector's Edition. Or bundles with a bunch of games, bonuses.