I learned something new today. I already knew the creation of the SUV and minivan models in the 80s was in response to the fleet fuel efficiency (CAFE) requirements implemented by the Feds. Those models were exempt from the fuel efficiency requirements because they were classified as trucks, not passenger cars. I assumed the crossover vehicles were also considered trucks. But I just looked it up and found I was wrong. The crossover vehicles are considered passenger cars, and must meet the fuel efficiency requirements. So I have no idea why they are so popular other than people just like them.
Wikipedia CAFE sub-entry on SUVs and Minivans.