The one thing that most everyone seems to agree on is that the site has declined,

This is interesting... I feel like this... but I acknowledge that it's mostly my lack of interaction that both contributes to this feeling for me, AND others. I don't know that the site has changed... people have. We get different jobs. We have births. We have deaths. We get new jobs. We graduate. People are in different places at different times, and the traffic on the site ebbs and flows. Sure... it's in a pretty big dip these days... but I'm not convinced it's a mechanical thing.

and that commenting is not great.

I still don't understand (but am trying). There's no doubt that chat has become an EASY way for me to interact quickly with the users on the site without dipping in to the bigger pool. When I have ten minutes, it's easier to pop in to chat and have some laughs than to read a goodlongread and then discuss it at length. In that respect, perhaps chat has reduced my commenting... but arguably, it brings me here more often than not, and then I stick around to read. In the end think comments here are so much better than anywhere else on the web.