The software industry, for example is filled with people who are extraordinarily talented at math in high school and thus get into the good schools. There are exceptions where people find the passion to code later on in life, but by and large, the "cream of the crop" fits the definition of the former.
Stephen King is famously a seat-of-the-pants writer, not knowing where his characters and settings are going to take him. He is also famous for reading constantly whenever he isn't writing or sleeping. Where other writers might avoid reading to avoid plagiarism or distraction, King eats books for breakfast, lunch, dinner and dessert.
R.L. Stine is famous for cranking out hundreds of horror novels. I recall him writing that a good horror novel requires a good ending, so he actually writes the ending first to make sure that it does. In contrast to Stephen King, he always knows exactly where he is going and about in how many pages.
It took (the non-prolific and perfectionistic) Gustave Flaubert 5 years to write Madame Bovary, and he wrote that he worked from 1pm to 1am (presumably shifting to 2pm when he started spending an hour a day tutoring his niece.)
Neal Stephenson famously quit email to apply more of his time writing for a larger audience.
I suspect his organization, methodology, and work style are partially responsible for his success.
I kind of wish we had been able to lock Sanderson in a room with George RR Martin to finish Song of Ice and Fire before Game of Thrones went past the novels.
There are plenty of grimdark authors that would be far better suited to finishing GoT.
He doesn't like the series, disagrees with Martin's pessimistic take on humanity, and believes the content clashes with his religion.
Quote from him:
"….the point is moot, as I wouldn’t say yes to finishing ASOIAF, if asked. (And I don’t think they’d ask me.) I’d respectfully decline. I wouldn’t be right for the job for many reasons."
https://www.reddit.com/r/asoiaf/comments/4uwjq9/spoilers_eve...