Comment by Sharlin

The sensitivity of S cones is also simply much lower than that of the M cones. It's clear that pure (0, 0, 1) blue is perceived as vastly darker than pure (0, 1, 0) green. Blue light must be about 10x brighter (in linear intensity) than green light to be perceived as equally bright; the brightest full-saturation blue in sRGB looks about as bright as the very dark green (0, 0.1, 0). The contrast on black background is incredibly poor.