This is why I don't pay much attention to GPU hardware performance comparisons at the high end to the degree I used to, because for one, display makers are taking their sweet time releasing products supporting the latest display port standard that's needed for said high resolutions at high refresh rates, and keep to display port 1.2 even today in the vast majority of cases, even though the technology is ready for far more.
Two, said displays would make any current high end card look like crap, forcing users to back down settings to get acceptable frame rates, which is what was the case in the early years of the GPU war, and an example of that is looking at the 32 bit color example at 1024*768 in the old days, and who could sustain that while hitting 60 FPS averages on a single GPU.....It took several years to make it happen, then there was the AA comparisons, which one was best and could be used with 32 bit color at which resolution.
Now imagine doing similar tricks, while trying to hit a 4K resolution @120Hz refresh on a single GPU, or even a 5K resolution@120Hz, basically going back to a proper GPU war where the limits of the hardware are being pushed, and weaknesses revealed......
These days we get to enable everything and the kitchen sink, and simply see who's got the fastest FPS and no, I don't find a 10~15 Fps performance difference at 4K as night and day issue, since most users aren't even willing to get a 4k display because they'll be limited to 60Hz refresh anyhow, so what's the point of waiting for even faster GPU hardware?......Faster 1080p and 1440p numbers?, give me a break as we've got plenty of speed there.
Seems that the display hardware industry in general is showing it's got no b**** or leadership whatsoever, and is simply remaining mainstream over their entire product line for the most part save for rare examples, and GPU makers would really have a challenge on their hands trying to make GPU's that perform well at those higher resolutions, so they they don't mind having an easier job and charging 700$+ for their cards, which is more money than most put on their CPU purchase.....