Natural selection in sports

Often in training people try to copy the most successful athletes training routines. This is because they believe that the reason the athlete is so successful, is down to the particular routine. In the skill aspect of sports, this is often the case. In strength & conditioning, not so much.
Generally athletes at the top of their game, perform way too much exercise for the average person to tolerate. Former Mr Universe, Mike Mentzer, often used to compare exercise tolerance to suntanning.
Just as there are opposite ends of the spectrum with regards to tanning (some people can only stand intense sunlight for a few minutes before burning, others can stay in it for hours with no problem), the same is true for exercise.
Some people can do very few workouts, before they become exhausted and overtrain, while others can train 2 or 3 times daily and still have enough energy to progress.
Now which type of person is more likely to become successful at their chosen sport?
Obviously the person who is able to train more often has the better chance of becoming successful, as their body can tolerate more volume and still progress. Now is it the training routine that has made them more succesful? Of course not! If their routine was designed more so they had adequate recovery, it is likely they would progress even faster.
Also, which person do you think is more likely to stick at the sport or exercise programme?
The one that gets tired and over trains very quickly, or the one that can train all day and still make progress?

This is natural selection in sports.