Tron, you got it backwards. For a given load, an engine turning higher rpm is using less torque at the higher rpm. In other words, power = torque times rpm.
When you use a gas engine to tow, going to higher gear ratio gives you higher engine rpm and your tow capacity goes up. One look at truck towing charts shows this.
What you sacrifice to do that is consuming more gasoline and faster engine wear to pull that load.
Which is why diesels are used with lower gear ratios - they have higher torque at lower rpm. But the rest of the drivetrain has to be able to take that higher torque at lower rpm - transmision, u-joints, drive shaft, etc. Diesels use less fuel and wear, but cost more to purchase, because their cylinder pressures are so much higher than spark engines.