Let's face it, hockey players are weird. They're creatures of habit that don't like changes to their routines. Some have a specific way to put on their equipment, some eat the same pregame meal and some never upgrade their equipment. Whatever it is, every hockey player has some kind of superstition.
Listen, Sidney Crosby is one of the greatest players to ever play in the NHL, but this superstition is just plain gross. The one part of your gear you should probably change more often than not is your jockstrap.
It's worked for him this far into his career though and if he's still able to wear it, even if it's barely being held together, I guess there's no need to change it.