What is 2160 other than 4K? I am not following.Why not game at 2160 rather than 4K? Seems like a bit of a stretch when not long ago it was 1024 versus 1280, then we suddenly started talking in television terms. Monitor manufacturers trying to scale out stuff way too fast for the videocard hardware limitations. 4K monitors can support 2K, so it makes more sense to me. Even though people insist you cannot see the difference between 60fps and 120fps, thats not true. Our brains all sync to different key frames and different people have completely different abilities to process. People used to use zoom to give 360 fov in games and it drastically reduced their need to process what they saw. The eyeball has the ability to only really see a small focal point in detail and those details fall off in the periphery. So regardless if its 1080 or 8k, your eyes see the same lack of detail outside the focal cone.
And anyway most games play fine at 4K on current (theoretically) $700 video cards.
A lot of games I play are pretty slow. Think Civilization or other map-focused games. Focal cone and periphery are not that important when you often slowly move your eyes over the situation. Maps look much better when rendered with higher resolution.