I wonder how much of this depended on the differences in device screens. In 2015 there was a lot more variability in display technology, lower resolutions in general and worse color fidelity. OLED was uncommon and expensive, you probably only had an IPS display if you worked in graphic arts, and a lot of people were still using standard LCD monitors backlit with fluorescent tubes, which meant that the black depth was limited and the detail in dark regions of an image was frequently not visible on the screen.