Bilbo the heavyweight division ALWAYS has "retreads" they don't get much quality new blood from lower weight classes and older talent that has been around the block can reestablish themselves in a big way with just a few quality fights.

Look at Andrew Golota, perfect example. He went from mentally unstable contender, to KO victim, to quitter, to joke, to contender, and IMO he beat both John Ruiz and Chris Byrd.