The problem with all these studies is they are not run of long enough time for full adaptation. Of course if you take the average Joe gym rat and make him do a true 10RM on a particular exercise, he will need 120s to recover enough to get 8 reps on the subsequent set. Instead of resting 120s, if you made him rest 45s you would have to lighten the load considerably. The bottom line is the metabolic stress of the first set would result in less mechanical stress in the second set, and that effect would only increase over the remaining sets.
All this sells the human machine quite short as far as I am concerned. Why cater to this? Why note continue to train with the shorter rest periods and progressively increase the mechanical load on subsequent sets? Eventually, after training this way enough, you get to the point were after that first 10RM set, you can get 8 reps after only 45s.
The end result is the ability to do more volume in the same period of time.