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.

Yes, there is a significant cost to being built differently regardless of perceived advantages (by one's self or others). For example, as an autistic, I have to cope with finding interaction with non-autistics quite difficult for me, even if detail-oriented thinking can make certain tasks seem easier to me.