It's interesting that these four HoF players have no rings whereas other players, who're originally earmarked for being *destined to be ringless*... Antoine Walker, Bob MacAdoo, Alonzo Mourning, Rasheed Wallace, Gary Payton, and yes, even Ray Allen, all have rings today by giving up the franchise-to-sub franchise player role.
I believe this is a source of Barkley's mental malaise. He's competing to be the best player w/o a title.
I think in the future, unless either Nash or Nowitzski find themselves as the fourth player of a deep squad, they might end up on that list from this current generation. I think both LeBron and Howard will get theirs, however, in due time.