Bottom line is that drive shaft RPM is irrelevant.  What really matters is whether the engine is in its power band when you need it to be.  Back when truck transmissions only had a 2.5 to 1 spread between high and low axle rations where much more important than they are with the newer transmissions that have a 7 or 8 to 1 spread.  
The op is correct, unless you find yourself in first gear wishing that you had a deeper gear or in 10th gear wishing that you had a higher gear you get the same effect by simply changing gears. 
I do suspect though that axles built with higher ratios may also be built to handle higher torque to the wheels, at least in some cases.