The thinking in some cultures is that because labor is difficult, having multiple wives (and thus more helping hands and more children) will help alleviate some of the work responsibility for one family.
John Mbiti writes of African culture: “Within the context of life, polygamy is not only acceptable and workable, but is a great social and economic asset.”
Here are several objections:
(1) There are more important things than financial security.
While it is true that women desire monetary peace of mind, it is fallacious to assume this is their chief aspiration. A wife wants to feel close to her husband and covets intimate time with him, indicating emotional security is more important than financial. Leah knew she was “hated” by Jacob (Gen. 29:31), so she named each of her sons in such a way as to woo him back to her, saying: “Now my husband will love me” (v. 32) and “This time my husband will be attached to me” (v. 34).
(2) Scripture rebukes those who circumvent God’s plan for temporal blessings.
Abraham, using similar logic, failed to trust in God’s plan and took another wife in order to bring about a perceived greater good (having the promised son). God chastised him for failing to trust.
(3) Fathers and Husbands must take more responsibility, not more wives.
It is the husband’s responsibility to lead, provide for, and protect his family. Scripture never indicates that polygamy is necessary to attain this goal. Rather, he is encouraged to trust God who will provide for all of our needs. A Tsonga proverb says: “An elephant is not borne down by the weight of his tusks”, meaning, “A man is not discouraged by his responsibility toward his family.”
(4) Multiple wives are expensive.
Polygamy is more often a hindrance than a help regarding economic growth in the family. Maintaining multiple wives is not cheap, especially in Africa where many people struggle through poverty. People today commonly fight just to support themselves, let alone their wives and children. Moreover, as globalization and technology permeates Africa, subsistence farming dwindles, making polygamy as a means of gaining more labor less likely.
Between Two Cultures 
Good objections. Can’t we also say that polygamy always promotes poverty in the long run because sin never is the most efficient way to create wealth? Polygamy cannot produce children who are raised up in the nurture of the Lord including a work ethic, moral restraint, and habits of Biblical communication in the family.
A man may make money from selling alcohol, but the effects that will have on his person, his family, and his society will actually be a net loss. Gambling brings in money for a casino, but the increased policing, rehabilitation, and lost labor productivity hurts the society more than it helps the few fat cats at the top.