MKG has always been bigger, stronger and more athletic (not explosive athletic as much as coordinated athletic) than his opponents. But in the NBA, he doesn't have those physical advantages as often, making his lack of a perimeter shot all the more painful.
James, of course, is and always has been the best athlete on the court for every game he has played since he was 15 or so. His ballhandling and quickness, far exceeding MKG's, enabled him to dominate the world without a reliable jumper. But to win a ring and defend the title this year without always taking a pounding on drives to the rim, James has developed a beautiful jump shot. It seems almost unfair, but that is what every top player must have to reach his ceiling as a player.