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We did it for five hours a day for three years, completely via the brain.
If you did it as a child, you are already smart and you believe it is innate talent. Instead of that stalled and accumulated effort, you've been used to all this work.
If you didn't, you wouldn't be able to try the experiment. As an adult, unless you suddenly get rich, it's very hard for you to cultivate that discipline, to study and bring yourself into acquiring enough knowledge that can help you in real world experiences.
Majority of your knowledge might come from just experiencing life and learning from your mistakes, We go to which is not the absolute or the better part of learning. Sometimes you need knowledge to have an edge.