I think that in many societies where men can marry more than one woman, it came about because women's work is somewhat boring. Personally, I find household chores a lot easier to do when I am talking to someone, and even easier when I am working with someone else on it.

If the men are off hunting, or working the fields, or at war, then it would be very nice to have another person about the household. (I even told my mother once when I was much younger, that I wouldn't mind it if my future man was married to more than one woman, as long as I was "first wife" and hopefully the favorite wife as well!)

But unfortunately, that structure in a society, although it has its advantages, it also constrains people too much into certain patterns. There will always be some who just don't fit. If they have no choice but to fit or die, then they'll die. Or their gifts will not be given because they are not allowed to give them.