Whatever GPU is for whatever resolution whoever buys it wants to run it at and get results he is mostly happy with. By toning details down a bit, you can push much higher resolutions out of a much weaker GPU. In many games, I find myself disabling some of the fancier GPU-hogging effects simply because I find them too distracting, they look incorrect or have glitches that bother me.
If I had a 1060 and a 4k display, I would likely find a balance of settings in most games that I'd call good enough to play at 4k. (Just for giggles, I have run games at 5760x1080 on my 1GB HD5770 and many of them were surprisingly playable without giving up too much on details beyond what I had already cut off at 1920x1200p.)