Problem is that people compare a diesel truck with 3.73 or 4.30 gears with gas pickups and SUV's that usually have 3.42 or even 3.08 gears. To get better fleet average fuel economy numbers the manufacturers but gears that are much too tall on their non work vehicles.
So with the gas engine that needs double the RPM's of the diesel to reach peak torque you have the factory pushing out vehicles with gas engines and higher gears, the exact opposite of what is best for the owner who plans to tow with their vehicle. Most of the problems with gas engines for towing lies with the buyers not understanding the need for lower gears and letting the dealer decide what to buy from the factory. With medium duty diesel work trucks the higher gears are usually not even an option so a customer cannot shoot themselves in the foot with their purchase.