Oddly enough emissions standards are one of the major reasons vehicles are getting so big.
In 2012 fuel economy standards were changed as a response to the manufacturers calling everything a truck to get around regulations (seriously - they classified the PT Cruiser as a truck in the 2000s). So now standards are weighted based on vehicle footprint instead of by class.
Notice how around 2012 was when the American auto manufacturers stopped making the old Rangers, S10s, Dakotas, etc? And now that the Ranger is back it’s as big as the older F-150s and the F-150s are the size of a small airport? And as the CAFE standards get tougher over time the vehicles keep growing?
It’s easier to just make the trucks bigger every refresh cycle than to make them more efficient, so that’s what they do.