I don't think it's surprising that older people have the <i>ability</i> to be so prolific. What's surprising is that they still have the <i>patience</i> to put up with all of the BS that goes along with writing software. When you hit the ten thousandth broken library API or build-system idiosyncracy of your career, it's tempting to scream "Enough!" and retire to farm fish or something. Ditto for dealing with well-meaning users demanding features to support an impossible use case, or not-so-well-meaning haters trashing you on Twitter/HN/Reddit. If you can <i>only code</i>, on what you want the way you want, without caring even one little bit if anybody uses or likes it, that might still be fun. Otherwise, all that other stuff gets pretty old, and that's more of a problem than <i>you</i> getting old. As you see your friends starting to pull back or retire altogether, and you realize that you <i>could</i> do the same, the idea gets pretty tempting even if you love to code.<p>BTW, since somebody's likely to ask, I'm 51.