Bynum isn't that good anyway. Never has been. And he's always in foul trouble anyway.
But his injury gives other teams more confidence, which is great. Even if Denver is missing KMart, they know they can beat LA if they're missing Bynum.
Lamar is a way better player than Bynum, so the Lakers' starting five is better with Lamar. But the bench suffers greatly.
The key to beating LA is not letting them get offensive boards and second chance points. If you limit them to one shot, then all those missed jumpers by Bryant turn into fast break points on the other end. If the Lakers fall behind, Bryant takes over, and that's when the Lakers are really in trouble.
The Lakers can't hurt you from three-point range. they may hit 3-4-5 a game, but they're not going ot hit 9-10-11 a game. They just don't have the shooters. They have to score twos, so if you keep them off the offensive glass, you win.
Denver, Dallas, Orlando, and Cleveland all have better three-point shooters and are capable of putting up 10+ threes every game. That's a lot of offense for LA to overcome, especially if Bryant is trying to do it by himself, which you know he will.