Here's my theory on the NBA: All truly great players are a generation ahead of themselves.Go right down the list: Bill Russell was the first truly athletic big man in the so-called modern era. Not the first big man, certainly. The first athletic big man. Ditto for Wilt Chamberlain, the first athletic 7-footer.Oscar Robertson was the first 6-foot-5 point guard, big and strong and a master at backing down smaller players. Elgin Baylor was the first great athletic forward, Michael Jordan, simply a different level athletically than those he played against. That's a trait all superstars share, regardless of the generation. Julius Erving was in that same category, bringing a kind of swooping athleticism to the game that rarely had been seen before.