I have to admit the white Xbox one is pretty sexy looking. At least from the Wii forward they have been making white consoles that don't turn yellow when they live with a smoker. He's looking at you NES, SNES and DC.
Some of those yellowed consoles are because of the plastic, while some others are because of smoke. Anything can become yellowed over time due to smoke, modern systems aren't any less prone to that situation than older ones.