At such cost with such narrow advantage, why has it persisted so pervasively? I would counter that the advantage is wider and the cost narrower than your current value system is allowing you to accept.
It is the sum of costs and advantages that lead to reproductive success. The trait is still here and still prevalent meaning people are still getting laid and starting families and presumably leading fulfilling lives.
As long as an organism isn't performing too badly, it stays in the gene pool. It can persist and even share its genes more broadly, if in diluted form, to the other more successful organisms. And then some of those mixed-genes organisms may occasionally express more strongly, but again not enough to affect reproductive success across the population.
