Lebron defies what seems to be knowledge of players lasting, as has Brady. I expect he has 3 top 5 all time player seasons left.
Lebron has the following against him having a long career:
He is heavy, power full leaper. not sure any NBA player has exerted or suffered more vertical force. Not easy on the joints.
He played a lot, including heavy minutes in the NBA, as a young guy when joints are more susceptible to damage, just like you don't have your high school pitcher throw 130 pitches.
He has had deep playoff runs almost every year, and player Olympics a few times. Lots of extra miles.
Lebron has the following in favour of lasting a few years:
He has shown little sign of losing any pop. He still gets up with the best, so doesn't seem like any creeping joint issues are going to slowly affect him now/
He has almost supernatural balance. Does he ever get knocked down. It is incredible how flies in a full speed off one foot, gets fouled and sticks the landing. Really incredible how he avoids falling, getting knocked down. He is the anti-Iverson in this respect.
He's not Kobe and that is good.
Kobe was driven by an obsessive work ethic, to the point he over did it. Lebron is uber dedicated, but stories of his level headed balance, taking a day off when his knee was sore, etc go back to his teens. He also can spend millions on the best info and advice for his personal training
Unlike Kobe as Big Sox fan mentioned he is a passer and facilitator not a maniacal scorer. Kobe never could make th late career adjustment to sharing the ball, playmaking that Jordan did. His game will age well.
People often cite his lack of edge compared to MJ, Bird, but his level head makes it les likely he going to break abone diving into a scrum for loose ball in a regular season game.