What you may notice from the other replies is that many of them conflict with each other. The reason is that this has much more to do with the rhythms of your own life and interests than with global trends. When I first started reading HN I would read several links a day. I don't think the quality of the links has changed that much -- indeed, many of the links are reruns that I've seen here 2, 5 or 10 years ago -- instead I have moved on to have more focused interests, and a higher level understanding in those areas, so that fewer of the posts are useful to me. (Meanwhile, I have much less time to read in general at my present stage of life, so I also read fewer books and magazines). I suspect there are also meaningful global trends, but extrapolating from your own experience will lead you astray.
This is a sensible take that could be applied to almost anything else in life with some exceptions. Do whatever works best for you, but don't generalize much outside of your practical experience.