Most of those people also get food stamps, etc.
Being LDS (Mormon) I have polygamy in my ancestors...many of the men were killed and women and children left alone, added to the concept.
But my Ggrandfather, Abraham Day III had Elmyra and my GGrandma, Charlotte and each of them had a mess of kids. He was a jack of all trades and kept both families well supplied.
But I would never have considered marrying a man who had or wanted more wives. I'm ornery that way.

PS. He went to prison for being a polygamist.