I've been arguing this point for years now!
Doc Rivers sucked!
He had PP/KG, both of whom in their mid-30s, playing all of the time, to maintain leads and give the Celts a chance of winning during those contender years, from '08 to '12.
And now finally, after all those years of me hollering at you, you see a Brad Stevens, learning how to utilize, EVERY MAN ON THE ROSTER, to maintain leads and perhaps, even win some games even while his equivalent of KG/PP were on the bench, nursing their wounds.
This is why I will never respect Rivers. Sure, if KG/PP were 24-28 years old and at 100%, game after game, they wouldn't need a team. They could hire a bunch of scrubs and go, 60-22, season after season. In effect, this is what Doc's strategy had hope for, in terms of being a regular championship contender.
Stevens, on the other hand, never had that luxury. He had to think and then, out think the opponents, game after game. In effect, if he had KG/PP, he may have been even used both of them as elderly co-sixth men, and won series.