the last contract LeBron signed with the Cavs is exactly 1 year shorter than the one he just signed with the Lakers
and unlike the Cavs- the Lakers main concern should be LeBron's longevity.
He will be playing in his age 34 season. Over the long term- erosion of talent is much more of an issue than is contract length. The Lakers can play it safe and not fold to LeBron's demands in order to win short term all they want since they have him locked up- but what does it matter if they have him locked up when he goes from being The King to just another pawn?
As great as LeBron is- does anyone think he will THE KING in his age 37 season?
Based on what the Lakers appear to be doing, Lebron won't have to be the best player in the NBA for the Lakers to win with him.
The idea this year is to let the kids learn from him and develop (apparently Kuzma has been shadowing him trying to learn whatever he can).
Hopefully, next off-season they will land a top FA to go along with him and the kids development so they can be contenders starting next season.
If the Lakers play their cards right they can have Lebron for a couple of seasons while he's still the best player in the game and then a couple of seasons when he's still a top 5-10 player in the league, but now has a bunch of young, really good players with him and another top FA.