Duncan and Nowitzki are pretty classy guys from what I know, so I'd say they are the exception to the rule. However, both are also nearing the end of their careers, they're in a much different position than someone in his prime.
Every year we see plenty of old veterans sign for significantly less money to play on a contender. But has there ever been a superstar player that's in his prime to do it?
Both Dirk and Duncan did it in their prime. Duncan did it to resign Parker and Manu, Dirk did it a few years ago to resign Kidd and go after a few others, IIRC.
