Your question is entirely valid -- there is a point of diminishing returns. The GS8, for instance, has a resolution of 2960 x 1440. By default it runs the scree

Your question is entirely valid -- there is a point of diminishing returns. The GS8, for instance, has a resolution of 2960 x 1440. By default it runs the screen at 2220 x 1080 and the overwhelming majority of customers will never know the difference. I have a Lenova 720 with a UHD screen (like the linked), and the vast majority of time I run it at 1920x1080 to halve, and halve again, the load on the GPU trying to run so many pixels (not to mention the occasional irritating software incompatibility with the resolution, leading to interfaces for ants). It is generally an imperceptible difference, and one of the very few times I go back to the native resolution is if doing an extended reading session of dense subject matter, where there's a minuscule advantage in type clarity. There is a placebo effect as well, so someone with their shiny new ultra high resolution screen may feel that there's a compelling difference, but I have doubts it would hold up under legitimate blind testing. We see the same thing with color perceptions now -- that OLED and a good LCD (e.g. iPhone XR) will be calibrated to close to identical color performance, and in blind testing will likely be very difficult to separate on that basis, but it's very common to hear OLED users laud color performance. There is no question that OLED absolutely owns when it comes to contrast, especially in dark environments where the difference between LCD grey and OLED black is without question.