I think part of this is the often dual use nature of these machines. Gaming consoles have updates every couple of months, which might be more often, but the systems are also left on or left in a low-power mode where they will still check for and download (and possibly apply?) updates, depending on how the power settings are set.

If you used a gaming console the same way you are using your main computer (booting it into a separate OS for most the time, until you all of a sudden wanted to play a game) you might also find that there's updates waiting to apply, and some games require the OS update before they'll play, etc.