Maybe 1:100 comments match any one of those attributes.

Most comments are just grammatically "correct". Not a high bar.

The comments that aren't grammatically correct get pedantically corrected by those HNers too, so that's nice.

It has, and the well prompted agents still give that. It's very weird.

I just don’t even understand the appeal of having a bot interact on forums for you unless you’re astroturfing for your company or personal brand or whatever