We have a pretty good indicator as to how a boxer's going to do in the long term at the gym. It's not absolutely-by-God foolproof, but we've found it to be darn reliable.
Simply put, we watch how they handle losing. It's easy to stay enthused and involved when you're winning. If, on the other hand, things don't go your way, how you respond to it tells us volumes. If, just to pluck an example out of the clear blue sky, you decide to storm out of the ring in a huff after a narrow loss, then that's probably a good indicator that people are not going to want you and your ego around for much longer.
This, pretty much, is why we have a vacant lightweight title at this point. It's baffling to me, in fact, that someone could think he could emulate being a sportsman without having to account for sportsmanship.
But hey, it's a big crazy world...