I think the character and virtues of a person also play some role in this. For example, my brother, who is a Gemini, is sometimes faster and creative than me. This results in a personality that is more suitable towards development works. I tend to be highly organized, but more of a jack-of-all type. I have dipped my fingers in many areas, rather than sticking to one.

One of my friends in college used to take 10% of the time I took to make the same programs, but he was a lot messier than me.

I have observed that such traits of a person appear in the work they do, and tends to have some impact on it. Of course, by certain effort, one can acquire the required qualities and give up the unwanted ones. Everybody has free will.

postscript: I am a believer that programming is an art, rather than science. Software Engineering is not merely programming, though.