Perhaps the convenience of modern life discourages having lots of kids. Since they're no longer needed to work the family farm, and are more likely to live past

Perhaps the convenience of modern life discourages having lots of kids. Since they're no longer needed to work the family farm, and are more likely to live past infancy, and will almost always function as a huge liability of time & money, why would a modern couple try to have more kids than are necessary for their own emotional fulfillment? That seems to be most people's unconscious driving factor in reproduction.