My opinion on the subject is only by knowing human limitations (your own and the limits of others) can you transcend them. I used the example of the body builder because this is something anyone can test for themselves. Anyone can lift weights in competition with another person and see which one has more natural talent to build muscle. This will show without a doubt that natural talent for building muscle exists and for this reason steroids were invented to allow people who don't have the natural talent to use a drug to achieve the results of people who do.
Now let's bring it back to "hard work" or "daily grind". This too benefits from talent and for this too there are products and drugs which can help people focus, help people work with less rest, help people to be motivated. In fact there is transcranial magnetic stimulation which has the exact effect to give anyone the instinct which comes to some people by nature.
Experiments have shown results where people have been treated for depression. Other experiments have shown by using these methods a person can feel like a psychopath for a brief period of time. This indicates that yes there is a natural talent because if there wasn't then these devices would offer no improvement.