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 don't think anyone is born smart, depends on each person's own efforts. Einstein was not born and then clever about mathematics, he tried and studied. Likewise with traders, you have to learn and try, if you keep trying and learning at certain times you can get even more expert