Pierce has quite a few years left in him - but in a Grant Hill-esque role, not as a #1 or 2 guy.
He has a few years of good all-around ball and 15/5 in him, and an occasional flashback game/half/move, but he can't carry it.
If we had a PG, we'd be the 1991 Celtics, with the aging Bird and McHale in Pierce/KG, Green as a young Reggie, Bradley as Shaw, Bass as Pinkney, etc. 2nd round out.
If we had Rondo and Sully, we're in the ECF again.