[theryan]

Diesel trucks tow heavy equipment (10k+ lbs) very fuel efficiently which is a common use-case in the states without needing to resort to a semi. Where I live a large number of people also own travel trailers and boats, which also lend themselves to diesel pickups.

I own a smaller truck myself (Ford Maverick) and tow a ~3000lb trailer with it regularly in the summer. My fuel economy goes from 30 mpg -> 11 mpg while towing. If I had a diesel, it would have virtually zero impact on mpg.