I'd just say hn is a reflection of the internet as a whole. And it is definitely not only HN that suffers.

Have you enabled “show dead?”

Yes.

HN got a new guideline because of it: https://news.ycombinator.com/item?id=47340079

While it was worse earlier this year, I still see a lot of ns;nt in /new, people looking to make money or get users for skinned or vibed products

https://blog.kinglycrow.com/no-skill-no-taste/

As far as comments are concerned, it's hard to establish causality but I have noticed being downvoted more often and lazier comments around 2022. But this could also be downstream of a more politicized climate. AI as a topic is also inherently controversial and divisive. People have strong opinions on either side of the debate.

Oh yeah lol. The hit rate used to be about 20% now its about 5%

It is has gotten far far worse. A new HN rule was added to refrain from AI generated comments and titles.

The "Show HN" is now full of low quality slop which just most of them breaks the guidelines and it is now "allowed" to link farm (usually with AI) and post + comment here about AI all day long.