We enjoy watching fights (be they boxing, MMA, or hockey) and don't care if combatants are vegetables at age 40
Sad, but true. We fetishize knockouts and brawls without much concern for internal bleeding and bruised brains. So long as it means a "good fight," we don't really care if Benson Henderson perpetually misplaces his car keys for the rest of his life. Athletes are replaceable and are only valuable to the extent that they can entertain us. Legends become relegated to car dealership commercials and early onset Alzheimer's and today's stars get their skulls whacked.