To my mind, the main reason is that the path to becoming a top athlete is full of struggles, and very few people are ready and willing to walk the path. First of all, becoming a stellar athlete requires lots of practice and conditioning, and this takes time. This is time athletes could spend with friends, studying for classes, sleeping, traveling and engaging in a wide variety of other pursuits. Also, becoming a stellar athlete requires lots of daily sacrifices that range from tiny to massive. For example, athletes may not be able to drink alcohol with their friends the night before a game. Athletes need plenty of rest and a healthy diet to be at peak performance. Being a top athlete means spending almost all the time training and competing, which isn't not easy. So as I've said before, becoming a top athlete requires intense effort and determination, and one must be willing to sacrifice what others are unwilling to give up.