Steam Hardware survey shows that 65% of people still game at 1080p
https://store.steampowered.com/hwsurvey
10% at 768 laptop resolution
5% at 1440p
and 2% @ 4k
Most of the graphics options within a game ARE there to make potato resolutions and low refresh look better with less jaggies. AA, Post processing, sharpening, blur etc.
When you get to 4k you can take out most of the settings that improve image quality for the lower most popular resolutions.
When we see reviews for gfx cards and lower fps for 4k resolutions - the only way to compare apples to apples is to turn every setting to max by the reviewers.
Some which just aren't needed at 4k and use up valuable processing power. At 4k you can turn off most of the rubbish settings in a game used enhance the most common potato resolutions, and free up the processing power of the GPU to render much higher frame rates than we see in reviews and get some very decent images and performance @ 4k.
All the graphical settings in a game have the numerous adjustments to cover poor hardware and low resolution right up to high end, high resolution and high refresh. If you get a game and turn up every setting to max at 1440p or greater....then you are doing it wrong.