Actually throughout history polygamy has been the norm. Even the xian holy book has stories of men in polygamist marriages desopite xians claim that a traditional marriage is between one man and one woman. The fact is that the traditional marriage is an arrangement between one man and more than one woman. I have 2 theories on why monogamy became the norm. 1. Men who were in positions of political authority or men who were wealthy wanted a lot of women for their wives so laws were enacted that limited most men to one wife and the men of the political class could have more than one wife at a time. 2. Somehow women convinced men that they should be limited to one wife who they would be faithful to for the rest of their life. I think it stands to reason that it is unlikely that a man came up with the idea of monogamy for all men. It had to have been a woman who came up wit that idea. It just is not natural for a man to desire one woman for the rest of his life.
Your #1 theory is correct. Wealthy males tend to have more women. We’re getting there. Then laws were enacted. Enacted by who? Political class? That’s correct too. Polygamy ration females to politicians and those they favor. See afghanistan.
#2 is complex. Democracy is mainly about FORCE, not people convincing something. Few things make sense with most political argument. I am not convinced that marriage is better than concubinage. But I faced strong social pressure to get married. We all are. As for wife convincing their husband. Well, many women (and men) don’t mind sharing. Polygamy and polyandry do occurs consensually if that’s what you mean. Also when voting, men and women tend to behave the same way. I may be a man, but I had a daughter and sister, for example, that also influence my voting behavior. So it’s not exact.
I think anti polygamy laws attract most single male voters. Anti women trafficking laws is preferred by most ugly single female voters. I may be wrong. At the end it’s voters’ interest, not the interest of consenting parties that matter. There are more singles than studs. So it’s normal that studs always get voted down.
Xian book has stories of men in polygamist marriage. That’s obvious. Did I mention that ONLY western civilization practice monogamy? Xian’s book, Tanach, is written during monarchy era. The interest of large numbers of single male voters don’t matter there so they have no problem with polygamy. In fact, polygamy is NOT a problem everywhere else except in democracy.
I do think those who opposes polygamy has a case. Polygamy always correlate with tyranny (like in muslim countries), while monogamy always correlate with socialism (like in western countries). That’s why I think we should abandon all “gamy” and concentrate promoting free market alternative.