Yes. Thats true but you are missing the point. Those who were deemed as talented in their field practiced developing their skill most of the time. Because the author of Outliers have said that both chris langan and robert oppenheimer both have equal intelligence but Oppenheimer became a successful scientist because of the environment he grew up in, where his parents encouraged his interest in science and Langan's parents were either apathetic towards his talents or they were unsupportive of furthering his talents. The author says that Bill gates love and talent for computers would not have developed if he did not go to a school that had a large computer, a rarity in schools in the sixties and he would not have spent much of his spare time on the computer at his school compared to his fellow students. Same case for the beatles.Quote from wiki about outliers:
"Outliers asserts that success depends on the idiosyncrasies of the selection process used to identify talent just as much as it does on the athletes' natural abilities."
He do not deny that talent exists, just that talent alone do not get you anywhere. The book is not to be taken as a scientific paper, but as a thought provoking text challenging the the common view of what a genius is.
But for example I believe that a large part to who can do maths and who can't is how well you can preserve your memories. Humans usually alters memories to fit the current situation, but if that process gets in the way of maths you will never be able to advance that high since your brain is then full of logical fallacies and you would create more of them constantly. So people who are bad at altering the memories would be better at maths, but at a cost since altering memories is a very important process required to tackle psychological issues such as depression.
Your environment can influence your performance in a certain field and can deter you from recognizing your own talents or potential in a certain field. The author gives an example that students at a school performed poorly in math , but when they went to a school that were more attentive to the students needs, their performance in math improved greatly. Jaime escalante improved