I wonder if polygamy is more of a loophole escape from sexual prohibitions. That is, people wanted to have sex with more partners but could not outside of marri

I wonder if polygamy is more of a loophole escape from sexual prohibitions. That is, people wanted to have sex with more partners but could not outside of marriage. In an age where access to premarital sex is plentiful, I wonder what motivations, if any, there would be for these first-class men to marry more than one. Multiple marriages, it seems to me, would be more of a legal and financial liability.