The issue isn't making babies. That we can do no problem. The issue is convincing people to spend money, time, and slow down their careers to raise the babies.
Capitalism raises the price of childhood. Birth control gives people the choice of when to raise kids. Education and equal opportunity provides more compelling life options then just staying at home raising kids.
The sense of local community, the ease of child care, sick care, food, housing stress all factor in to intentional family planning.