It's a mix of the CAFE laws and consumer habits based on decades of unsafe street design pushing consumers to larger vehicles which makes them feel safer and anyone outside them less safe, which makes them lean toward larger vehicles to match. Viscous cycle and arms race. Point being policy is part of it, but consumer behavior isn't blameless.
safety concerns caused cars to get bigger, everyone wanted to protect their children in a range rover but couldn't afford one, so other companies started making tank suv's
Congress made a fateful decision when it established CAFE. Instead of setting a single fuel economy standard that applies to all cars, CAFE has two of them: one for passenger cars, such as sedans and station wagons, and a separate, more lenient standard for “light trucks,” including pickups and SUVs. In 1982, for instance, the CAFE standard for passenger cars was 24 mpg and only 17.5 mpg for light trucks.
Put simply, there's a loophole in the emissions standards. If the vehicle is bigger, it has a lower mileage standard to meet. Manufacturers responded by making vehicles larger.
there is not more to it than that, safety standards in the 80's were "good luck and god bless", safety standards and demands from consumers currently and for the last couple decades are looking to protect children from being decapitated in automobile accidents, and have dictated the size and weight of what's being demanded and produced. SUV's make up the VAST oversized majority of the massive vehicles on the roads now, trucks/utility vehicles a VAST undersized minority. this argument is being made in a echo chamber, the issue is safety, and you're not going to convince families to put their children in the "yolo mobiles" of the last century, when literal tanks are on offer.