Injuries breh. The Lakers have an old star and a historically brittle star. They were blessed to make it through last season, but that demon can always surface.
Other possibility is LeBron taking a step back (especially on defense) and the Lakers just not being able to guard a team like the Clippers if Lou/Kawhi/PG13 actually play as they're capable of.
Lou is 34 and losing Trezz hurts their bench which potentially puts more pressure on Kawhi and PG. Lakers bench is set up to allow LeBron to sit more than he ever has.