Why was it possible to have three wives and four concubines in the past but not now?

In the past, we could have "three wives and four concubines" because that era was relatively primitive and had an old social concept that favored sons over women. At that time, most women stayed at home and relied on men for their economic lives. But now, we cannot have "three wives and four concubines."

The only "monogamy" system was established because of the changes in the times.

But the key to the problem is that it is not a system of three wives and four concubines at all, nor is it a system of monogamy. Rather, in modern society, it is no longer the farming era, but a stage of improving living standards, and various information

After the popularization of science and technology, people's lives have gradually improved. Men and women no longer need to be overly dependent on each other, and all kinds of contact will be reduced. The concept of marriage has also changed a lot, and people have become unmarried or divorced.