I've never seen that, most of the best boxers I have seen are coachable athletes who stick with it. Evander Holyfield said that when he started there were lots of kids his age who were as good or better than him. He said they would get a girlfriend or some other "distraction", stay away from the gym for awhile and when they came back, he would be better than them. Mike Tyson said that he would wake up in the middle of the night and shadow box to improve. Ali worked hard as a teen and young boxer. That's my experience, the ones who work hard, learn correct technique, or "mechanics" (that you apparently don't value), are the ones who prosper in boxing. The ones who come into the gym with a reputation as a tough guy or a physical freak seldom work out. They usually don't like it when they get hit back and they stop coming around. We all have different experiences in life, but my experience has shown me that guys who fight like Max Baer are not effective in the boxing ring. The only place I've seen guys that fight like Baer have success is in the fantasy land of the movies. And don't compare slow, stiff, mechanical Baer to Deontay Wilder. That is like comparing a plow horse to Secretariat.