[lmm]

Because Reddit is a moving target. At any given time HN is of a similar quality to Reddit-as-of-three-years-ago and declining towards Reddit-as-of-now.

[Joeri]

I’ve been on HN for many years and don’t notice this decline. Could it be that those who observe a decline in quality simply have gotten more sensitive to low quality posts with age?

[lmm]

It's possible, but I do sometimes look back at comment sections from years ago, and the change seems very real.