One thing you, Scar and myself share here is criticism of Joe, and we can't really compare Khan to Joe now. Joe only used his passport on 2 occasions during his SMW reign.
Khan's record and career entirely makes Calzaghe look as terrible as his career truly is. It's enough insult that Froch made Calzaghe look like a joke rather quickly too.
True, Khan has just recently begin to act a little bit like Calzaghe around after the Garcia loss, but has in the past took on some challenges like facing a tough challenger Peterson at his hometown. On the level though, if Khan - Brook fight still makes sense in a couple of fights down the line and doesn't happen because of Khan then his avoidance of Brook would classify along with Calzaghe's career.
Khan is doing this nowadays to secure a payday against Mayweather. Though to be fair, he's still fighting top opposition. Collazo, Alexander, Diaz and Algieri are no joke opponents. Calzaghe was staying in his hometown fighting bums simply because he didn't want exposure. The fact that he never pursued unification till Lacy and Kessler pursued him says enough about the guy.