How do people stop? They have to work to get food and shelter. They want stuff for their families.
Further, this isn’t just happening in the US. Go onto Google Street Maps and pick twenty cities at random all over the world. Every place looks the same. Same rows of houses, apartment buildings, highways, cars, factories, airports, shopping malls, and all the rest.
Yet, knowing we are going over a cliff, people still insist on having more children.