Take away Lebron's strength and what do you have?
A solid shooter who can still jump out of the gym and outrun 95% of the players currently in the league and has an insanely high basketball IQ. LeBron wouldn't be LeBron without his strength, but he'd still be damn good.
But the point is that Kane's physical advantage was, in most cases, due to his being much older than his competition. Being 4 years older when you're talking about guys aged 30-26 isn't such a big deal. Being 4 years older when the younger guys are still maturing physically is a huge advantage that Kane won't enjoy in the NBA (at least not very often). The playing field between Kane and his competitors is going to get more level; that's just a fact. The chances of someone making the playing field between LBJ and the rest of the league are pretty low. Nobody else has the kind of skills/talents/gifts he has, and it's likely that no one will anytime soon.