Hypothetically, if guys are expendable, you might find yourself in a situation with relatively few of them. In that circumstance, I do admit that polygamy can work better than monogamy. So, viewing men as expendable, ironically, can lead to polygamy.
You just messing with me? There's no sex ratio imbalance and no older brothers have died, leaving a wife without offspring? Why are you labeling my post that way? Polygamy is complicated, even if I were not at all romantic.