Lebron James will not be leaving Cleveland because he realizes no other team has been set up to take advantage of his assets. Playing in another system will actually hurt him no matter how inviting it may seem.
His strength, speed and power is maximized by Cleveland allowing him to handle the ball on the outside and moving towards the basket. Lebron will be taking a chance if he moves to a team that plays inside out or wants him to post up more.
He is a lot like Magic Johnson. Both were freakish players but you must design your team to take advantage of their unique skills. Magic would never be known for the player he was if he played in another system. That is why he fought hard to prevent not have certain players on the team or a coach who would not put himself in a position to excel.
Cleveland does not get nearly the credit it deserves for allowing James to develop and play to his strengths. And James is smart enough to understand that.
He will stay in Cleveland and it won't be just for the money.