Upon further reading, I think I am wrong here. My confusion was that I read that over 60% of the cones in ones eye are "red" cones (which is a bad generalization), and there is more nuance here.

Given equal power red, blue, or green light hitting our eyes, humans tend to rate green "brighter" in pairwise comparative surveys. That is why it is predominant in a perceptual luminance calculation converting from RGB.

Though there are much more L-cones (which react most strongly to "yellow" light, not "red", also "much more" varies across individuals) than M-cones (which react most strongly to a "greenish cyan"), the combination of these two cones (which make ~95% of the cones in the eye) mean that we are able to sense green light much more efficiently than other wavelengths. S-cones (which react most strongly to "purple") are very sparse.

This is way over simplifying here but I always understood it as: our eyes can see red with very little power needed. But our eyes can differentiate more detail with green.