When you look at the cap and bringing guys in, the salary is egregious, however; the marketibility, endorsements, cache, world renown and he's pretty much the face of the NBA it's definitely a sound investment. He's regressing and will continue to do so. Once he starts to buy in to Bynum and Sessions as the youth the Lakers will be fine. Will he do so, as history has shown are in spurts it's a waiting game.
There is no one in the NBA like Kobe. There are better players at this stage of his career, but no one is as important in the scheme of things.