For the most part, fighters remain healthy and well into their later years. Of course, there are outliers who end up with mental damage and go off the rails. However, how is it that so many fighters are able to sustain damage and remain mentally stable and well? For example, look at Poirier, Smith, Bisping, Paul Felder, Jim Miller, Cerrone, the list goes on. They are well spoken, seemingly intelligent, don't seem to have much issue with CTE, despite the wars and damage they've sustained.
Also, even though Max Holloway and Gaetjhe are well known for crowd pleasing styles, they both seem mentally all there, despite those wars and damage sustained. I'm just wondering why it is that many guys don't live with obvious brain damage from years of hard sparring and fights. Is it just luck? Is it a case of those that reach the top are there for a reason, and that reason is because they can give out and sustain more damage than most. Obviously, someone with very poor punch resistance will be found out far sooner than by the time they get the chance to the reach the UFC.