In the next few decades, we will see large families become common again in the US. Democrats and Republicans alike advocate privatizing — or eliminating altogether — Social Security, Medicare, Medicaid. The more extreme want to eliminate public education (Dick and Lynne Cheney were among this number). The most extreme want only two public institutions — the military and domestic enforcement, largely to adjudicate contractual disputes.
A future without the social safety net on which Americans have come to depend. Large families will again serve as insurance against the infirmities of old age.