So when do you think they should have stopped?

It is very strange that there is no damage on the rest of the wheel and even the wheel weight is still there. For that to have happened the wheel had to be locked up solid. When I first saw the picture I thought the tow truck driver had to have done it and just kept dragging the van until the tire was gone, then the rim was ate up too.

and even if it was locked up, the car would not drive right, you'd be binging the living piss out of that engine just to move a few feet. Let alone a few miles.