I think this is more of a selfish thing, I imagine that this person probably did not think it would be better for the world that he research D or E instead of A, B, and C, merely that it would be better for himself if he did so. Better to be a big fish in a small pond than a small fish in a big pond. See also: http://www.gwern.net/The%20Melancholy%20of%20Subculture%20Society
I think this is more of a selfish thing, I imagine that this person probably did not think it would be better for the world that he research D or E instead of A, B, and C, merely that it would be better for himself if he did so. Better to be a big fish in a small pond than a small fish in a big pond. See also: http://www.gwern.net/The%20Melancholy%20of%20Subculture%20Society