The Celtics absolutely pwned the Lakers in the finals. LA blew historic leads at home and was not competitive on the road. Laker-hater #1 (Bill Simmons) has a theory about why:
Boy, Kobe sure seems to have trouble scoring on these Shane Battier/Paul Pierce types, doesn't he? If someone's a little bigger than him, stays between him and the basket and has the reach to contest his jumper, and if that person is flanked by smart defenders who remain aware of what Kobe is doing at all times, it sure seems Kobe has trouble getting the shots he likes. Not to belabor the point because it's a moot discussion at this point, but MJ didn't have a "kryptonite" flaw. He just didn't. Of everyone from the '90s, John Starks probably defended him the best ... and it's not like Starks was shutting him down or anything. He just made MJ work a little harder for the points he was getting anyway. The point is, Jordan did whatever he wanted during a much more physical era, and when he faced great defensive teams -- like the '89 and '90 Pistons or the '93 Knicks -- nobody ever shackled him or knocked him into a scoring funk. Kobe? He looks a little lost offensively against the Celtics. It's true. Same for the 2004 Finals against Tayshaun Prince, another lanky defensive player with a good reach. Just remember to mention this on his NBA tombstone some day.
I do think the turning point in the series was Paul Pierce's defense on Kobe in the second half of game 4.
However, I think you can make a stronger case that the whole Western Conference is/was overrated. The Lakers won the west easily and got crushed by Boston. In contrast, Atlanta and Cleveland both took the Celtics to 7 games!
I know Kobe is the MVP and that his stats against the Celtics were better than LeBron's were, but I'll take LBJ in a heartbeat over Kobe any day.