Strict moderation is the reason HN is the only reasonable discussion forum remaining on the internet. I wish good moderation was a skill that more people learned - would you ever be interested in writing a guide or teaching a class on moderation?
Not at all. It's rather the community that makes it a reasonable discussion space. Most people here understand that this is not Reddit and that proper answers are needed when you interact with other members. Of course moderation is useful and necessary in certain cases, but it's certainly far from being the key factor here.
Nowadays the mod system remains but the community has moved on and although the stories are good, there is no intellectual discussion.
A similar thing happened to OSNews. Another news aggregator I used to visit a lot.