Emissive light sources in nature (except for rare occurrences like lightning, certain jellyfish and cherenkov radiation) are all black body radiation.

That's very different from the colors and contrast ratios possible by modern OLED monitors. The best example would be the blue LEDs used in modern OLED panels, which when they were introduced had a strange unnerving blue glow because that color just doesn't exist in nature.

Additionally, the contrast ratios possible by modern OLED panels are also far beyond anything in nature, as in nature anything that is bright, be it reflective or emmissive, will as result also light up its surroundings and reduce contrast naturally.