I feel you guys but I don't feel the comparisons are apt.
Who honestly gets more callers for appearances Jigga or Buckshot/OC/AG/Jake, etc.?
Jay-Z is a BUSINESS MANNE!
As far as 9th goes I'm pretty he made the time since the last joint went so well, I guess you could say they had good chemistry *wink*.
Jigga sells out stadiums, and they sell out a club, maybe depending on the artist. The only folks really checking for OC & AG like that is tru-heads.
Jigga and Piper that's Clash of the Titans. The indie circuit can always make time for one another especially if they work well together.