Even if that's true, consider how long it takes to type the command to reboot a server. Let's say pg reboots it 70 times a year. So, maybe he spends 1 hour to 1.5 hours a year rebooting HN. That's a better use of time than spending 2+ hours to make the site more scalable. There's no one he's interested in (i.e. deal flow) who's going to stop using HN or applying to YC because the site goes down every 5-6 days.

There may be all kinds of other reasons to update the code, but that comes down to available time, experimentation, and enthusiasm, not productivity.