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.
With math you cna know about the profit and loss happening with time upon the trade done. Trading is completely panicking, because even a small variation in the decision made in trade will let you experience loss. Most of the traders here were with large scale funds and they don't fear even if they experience loss as it won't disturb their living.