A similar effect: The average age on the internet is younger than you, and will be for the rest of your life. Think about what effect that has on the density of quality user generated content.
Current estimates put the average age on the internet at about 37.
I think this is a very plausible explanation, we are all at different points in the learning process and can only enjoy certain material. All but the most trivial programming articles are above my head right now, and so while I might enjoy them a lot; the HN community would say they are fluff pieces.