This includes the modern world. For any individual, they come into this world and, wherever they are born, there are certain resources around them. In the modern world, our world, this environment is very rich with resources. Note that this means anyone from an oz overweight to those weighing several times the weight of most people their height and age. So we live in an environment that is rich with food to a degree probably never seen in the human past.
Technology is the mechanism, the lever, that continues to increase the richness of our environment.
Male aggression is one factor driving these phenomenon. And the nuclear family itself is a consequence of our technology. It was not possible for single families to survive before our modern age. The rich environment of the city made the modern family possible. At some point intelligence, and the ability to manipulate matter and energy, primarily fire, began to change the tribe and made the invention of new human institutions possible.