Somehow I got to the opposite conclusion with yours. If the gap is because of practice and training rather than innate ability, the gap would be even BIGGER, not smaller. Essentially because the better you are, the faster you will learn more stuffs (which is already obvious to most people - we just don't really know if there is a threshold on learning, essentially the point of our biological limit). And because while the innate difference is unlikely to be 10x between human, the time spent on practicing and learning can easily reach 10x difference between the top and the average.