Tim Harford in Slate:
A lot of the knee-jerk reactions against polygyny are from people who can’t add up. In a society with equal numbers of men and women, each man with four wives gives women the additional pick of three men—the poor saps whose potential wives decided they’d prefer one-quarter of a billionaire instead. In the Sahel region of Africa, half of all women live in polygynous households. The other half have a good choice of men and a lot more bargaining power.
It’s hardly surprising that in most polygynous societies, the bride’s family gets large payments in exchange for her hand in marriage. If polygyny combined with women’s rights, I bet we’d see more promises to wash the dishes. Not everybody would have to share a husband, but I can think of some who might prefer half of Orlando Bloom to all of Tim Harford—including my wife.