This is the old "Nature vs Nurture" debate unrolling again. The author is taking the side of Nurture: only training/time/study counts. And he is dead wrong. So

This is the old "Nature vs Nurture" debate unrolling again. The author is taking the side of Nurture: only training/time/study counts. And he is dead wrong. Some people are better at some tasks than others. No amount of practice will allow a deaf (or even a tone-deaf) person to become a great musician. Tall people can clean the tops of refrigerators more easily than short people and that will always be true, no matter how much a short person practices. Secondly, this obviousness extends to all genetic traits. We're (almost) all genetically different and it adds up to a tremendous difference in behavior. This question really isn't worth discussing once identified: the "tabula rasa" theory supported by the OP is defunct.