That sounds like a trend of two. I think it is more likely that both Stephenson and Doctorow were programmers earlier in their careers (implied in their Wikipedia articles -- Doctorow founded a software company and Stephenson switched to a physics major so that he could "spend more time on the university mainframe"). And once you know a text editor really well (any text editor, even Word), it is simply most efficient to keep using it; there are apparently still professional writers who won't use an editor that lacks WordStar keybindings.
However, it would not surprise me at all to learn that there is significant overlap between "people who learn to program" and "people who want to write sci-fi novels". I just don't think we'll hear about Toni Morrison picking up emacs anytime soon.
However, it would not surprise me at all to learn that there is significant overlap between "people who learn to program" and "people who want to write sci-fi novels". I just don't think we'll hear about Toni Morrison picking up emacs anytime soon.