People in the suburbs buy SUVs instead of minivans not because they need the four-wheel-drive capabilities, but because the SUVs lack the minivan's close association with low-prestige activities like parenting, and instead provide the aura of high-prestige activities like whitewater kayaking. Why should kayaking be more prestigious than parenting? Because parenting isn't prestigious in our society. If it were, childless people would drive minivans just to partake of the aura.
I had foolishly assumed that people are having fewer (or no) children for a variety of reasons, the main ones being:
1 The increasing availability of various forms of birth control.
2 The large number of people who finish their education deep in debt.
3 The extention of adolescence in a prosperous society where lots of people go to college and grad school.