Again, it depends.

I think it would be more accurate to say that AWD *may* power as little as two wheels. But then again, so may 4WD.

The Quadradrive AWD system available on the WJ and WK JGC has a differential in both axles that can vary torque up to 100% to either wheel on that axle. It also has a transfer case than can vary torque up to 100% from the front to the rear axle. This is real AWD, but can push up to 100% torque to any wheel or a combination of wheels and performs very well, even compared to a fully locked up rig. It is slip based, and so it will push torque away from slipping wheels, so you don't have the problem with many limited slips type systems where they do not send the power correctly to the wheels that need it. And then of course, you can lock the transfer case so the front and rears are locked, but then it's really a hybrid of AWD and 4WD as is your example of AWD with locking axles.

Compare this with 4WD systems where at worst, you drive one front and one rear. Then, maybe you have a locking option for the front, maybe you don't. Usually this is an option the buyer must know to purchase. Even then, your rear may or may not be open. Possibly you get a limited slip option for the rear. In rare cases these days do you get a locking option for the rear.

Bottom line, I don't feel you can't generalize with current AWD and 4WD systems. The buyer must study the AWD or 4WD system(s) available in the vehicle on an individual basis.

An aside: Of course when people refer to "2WD", the system may only power one wheel. RWD, "2WD", FWD all may refer to one or two drive wheels depending on the system.

And of course, you must compare to system to the intended use.

-john