Ask HN: How are some people exceptionally productive?

Some people seem superhumanly productive. For example Hadley Wickham (ggplot2), Taylor Otwell (Laravel) etc. They are creators as opposed to managers (who have the luxury of delegating and managing). How can they produce so much consistently, at such a high quality?

If you are a highly productive person (and yet have a good work-life balance), could you share your methods?