I would too, but I am stuck for now at 1080 because of my current Display ( a 55" OLED TV at 1080p) ! So until I have the money to buy a new OLED TV ( Im gonna go 65" 4K OLED, which is around 2500 USD), I'm gonna play at 1080p ! That is the reason why I was thinking to upgrade my CPU+MB+RAM now, cause my current GTX 1060 6GB is running everything fine at ULTRA (turning down the AA a bit and maybe some shadows) !
So my logic is this: I go for the upgrade of the CPU+MB+RAM now and by the time I have the money to buy a new 65" 4K OLED Display ( in fall next year, hopefully earlier), GPU's will drop their prices and probably, I can get a really good deal on a RTX 2080 SUPER.
If I stretch my budget now, which will probably mean buying a 2070 SUPER, I will not benefit from it, because of my current TV, so no point in investing in something that I can't use.