The argument I have with the Tyson Fedor comparison is that Tyson fought everyone he could during his reign and he didn't avoid anyone. People argue he avoided Evander but they did wind up fighting. There are MANY fighters Fedor could have fought and didn't... even when he was in Pride he never faced Sergei, Werdum (who later beat him) or Barnett. After that Couture, then many challenges awaited for him in the UFC that he did not face. Then Overeem. So many fighters Fedor avoided facing up to now at his relatively young age of 34.
The only chance Fedor would have had to fight Werdum in pride was when the 2006 openweight grand prix was going on, but Fedor could not compete in that due to injury. Even if Fedor had been able to enter the tournament, Werdum lost to big nog in the quarterfinals so they wouldn't have ended up meeting anyway. As for Barnett, it beats me why he was never chosen to fight Fedor in pride. He had some impressive wins. I guess there were just others in line before him. Although that fight was gonna happen in 2009, but Barnett got busted for steroids.