Also since you want to categorize the likes of Okeafor, Bret Berry, and Antonio Smith as core guys then I'll throw in Ben Patrick, Ben Graham, Duece Lutui as well. Really bad argument.
Turnover happens to every NFL team. You think we've turned over any more than the Steelers since we met in the Super Bowl?
I'm not saying that we'll never be able to compete without those guys.
I'll buy Adrian Wilson (though he stunk in the playoffs last year) and Deuce Lutui (he's a player that I like more than maybe the front office does). But let's not pretend that just because a guy was on the roster he's a core player.
Graves identified Dansby as a core player and intended to re-sign him. Just because he got a competitive offer somewhere else doesn't mean that he was chopped liver on the field. He was a captain and our #1 defensive playmaker. Antrel Rolle wasn't consistent, but he was probably our #2 defensive playmaker. Warner--obviously--is irreplacable. How many times did Whis and Graves say that Anquan Boldin was a core player and important to the success of this team?
Do you really expect me to believe that Steve Breaston--a guy who isn't going to be on the roster in seven months and who the Cards aren't going to put up much of a fight to keep around--is a core player on this team? Really? Why not Ben Patrick, too?
To me, core players are guys who help you win football games. Right now, I believe that the core group that the coaching staff is going to try to keep together are Campbell, Dockett, Wilson, DRC, Fitz, Lutui, and maybe Levi Brown if he shows that he's worth his draft status.
But let's not pretend that we have all the core players from our Super Bowl run and last season's playoffs. Campbell hardly played the Super Bowl season, both our pass rushers are gone, a Pro Bowl WR is gone, and a potential Hall of Fame quarterback is gone.
EDIT: On your last point? Of their core players? No, I don't think the Steelers have turned over more. Pittsburgh's core players are Harrison, Woodley, Ike Taylor, Polamalu, Aaron Smith, Casey Hampton, Ben Roethlisberger, and Hines Ward. Pretty much everyone else is interchangeable.