Some states do not require titles to register older vehicles. When I recovered my m1009, I drove it home, and it was registered, and insured. Not everyone who drives a truck home from auction is a law breaker.
I agree and think you are completely correct - for the part of the recovery that was OFF BASE.
I guarantee that every base has a minimum set of requirements for someone to legally operate a vehicle on base. What is happening at MOST bases is those requirements aren't being enforced (or even thought about) because your trip starts on base.
If you stopped at the pass and decal (or whatever it is called depending on branch of service) and told them you would be operating your M1009 on base they would require you to show plenty of paperwork. Some of it would be impossible for you to provide because you don't have a title, registration, etc yet.
Since people driving MVs off a GL lot is such a small percentage of the traffic a base gets, very few bases have even thought about it. If you look at the GL website and see what all they sell, you can tell that most of their surplus is trucked off.
I don't have 1st hand knowledge, but I suspect that the bases that are actually enforcing their already in place rules (which means no drive offs) are the result of something bad happening or a close call.
Again, I'm only discussing the portion of the recovery from the GL lot to the painted line outside the gate. After that as long as your truck is road worthy and insured you should be ok.