Something we might be forgetting with the CAFE standards is that they are easier to meet than the regular EPA standards.
EPA vs CAFE: The Two Sides of Fuel Economy Numbers » AutoGuide.com News
Manufacturers also get extra credit towards that by being able to count electric cars they sell twice, and trucks don't have to be as efficient as passenger cars.
Most people with a truck don't actually need it. My boss, he needs his truck for the business, but he's got a small one (Ranger) and he doesn't drive very much with it. Plenty of people I know have way too much car for their actual needs. But that's the American way. Everyone has car-size-anxiety here.