Unlikely, but the point is that the car kept getting returned, so it was (reasonably) safe to assume that it would continue to be returned after each crime spree. Sure, the thief could have crashed the car at some point, or gotten caught (and the car impounded), but I think it's not entirely crazy to judge that risk worth the benefit of the free gas.

Now, I probably wouldn't come to that same conclusion, even if I had a cheap/old/crappy car, but I can see how someone might.

Back in the good old days, a friend of mine had a sticker on his Citroën 2CV reading: "Can you also double the value of your car with one tank of fuel?"

Entirely possible [1].

Now in this case there was a disposal fee for old cars so if someone could take it off your hands for less, it was a win.

[1]: http://www.jeremyclarkson.co.uk/cheap-car-challenge/

Probably not but why would it be relevant in that case?

A full tank over the course of a year or five.