It would be a bad business for Konami to release an MGS exclusive to Xbox when most of the IP sale come from Playstation but an new IP exclusive to Xbox could happen.
PS4 - over 100 millions let's say 120m
Xbox One - 70m
Wii U - 25m
Vita - 15m if it will not get Final Fantasy Kingdoms Heart and Monster Hunter 20m otherwise
3DS - 80m