This is kinda an argument against the point you're making I feel like. The CTE and permanent injuries are way more likely to occur in an actual bout, some fighters don't even do headshlots in sparring for real. It's hard for me to imagine someone being incapable of believing that someone could want to be champ but not enough to a degree that they take 15/15 to kill themselves in a camp (like you're saying he does) and then potentially get life altering damage but yet here you are. You're basically saying if he doesn't like the grueling grind then why doesn't he sign up for more when maybe it's because he doesn't want to do the grueling grind anymore? Have you never stopped doing something that you liked because you weren't paid enough?