Imagine a trailer takes 1 unit of energy to move, and ICE truck takes 5 units to move itself, and EV truck takes 1 unit to move itself.
The ICE truck towing it would go from 5 units to 6 units, reducing the range by 16%.
The EV truck would now go from 1 unit to 2 units, reducing the range by 50%.
So the better your efficiency, the worse you are at towing. Ideally EV trucks would have such a huge battery that even when the range is reduced by 50%, it is still as long as a gas truck's range, but modern battery technology is still too sucky to achieve this.
Not so sure about that one, boss. I can fully-load up a Ford Ranger to its 7500lb rated towing capacity and lose ~10% in fuel economy/range while you just dropped something like 30% (from the base power package range of ~240 miles, platinum package at 300 miles you're losing half if you only get 150 miles out.)