The folks who really care about tow ratings and range are those who have boats or campers. Which means they do road trips while towing. Do you want to tow a camper on a road trip in a rented vehicle?

Yes, gas trucks also suffer poorer fuel economy when towing. It's less of a practical problem because it means more 10 minute fuel stops. With an EV, it means more 3 hour fuel stops. It's fairly easy to equip a gas truck with a larger or additional fuel tank. My S10's fuel tank is on the left side of the bed; it would be fairly trivial to mount another tank on the right side, or, a Blazer's fuel tank isn't that hard to install behind the axle where the pickup hangs its spare tire. Doubling or tripling a pickup truck's range is something a guy can do at his house. It's functionally impossible with an EV.