A couple reasons might be the chicken tax (25% tariff on all imported trucks) and if it's "too small" it might be in the category of light trucks where the EPA

A couple reasons might be the chicken tax (25% tariff on all imported trucks) and if it's "too small" it might be in the category of light trucks where the EPA imposes very strict fuel economy standards. I blame regulatory capture for both of these things. Gotta protect American big truck manufacturers from competition from smaller, lighter, possibly cheaper vehicles.