They are made, but it helps if you were born smart
I think innate ability is very important in determining the performance at the projects you undertake. A person good at mathematics might not be very good at cellular knowledge. It also depends on the training you get. Normally, a period of six months is more than enough for someone to specialize in a field. If you are not good at trade, you can become the best trader by exploring and practicing.
I think i can be example, i am good at math but in trading i can't beat panic that come if market move very fast. That is why i can't be good trader until now. And i already trade for a years, still always panic.