They were never that great IMO. Kobe is awesome on D but no one beyond that is great. Gasol is well below average and Odom/Bynum are more statistical defenders than lockdown guys.
Plus they score alot of points which generally leads to other teams scoring more points on them. Don't ask me how it works out. A team like Golden State or Phoenix in previous years has that run and gun style that lets the other team break easier but the Lakers play slower. Maybe mental? Who knows. NBA is a mindfuck for me.