That's quite a premise! I disagree with it extremely strongly.

People mostly don't go back to any HN thread that's more than a day old. So any conversation that requires more than a few hours of thinking can't happen here, because by the time you finish thinking hard about what you just read, no-one is reading anymore. How could that possibly lead to the superior intellectual forum on the web? It's a place for people to share their initial opinions about something in response to news. That can be good! Often people have interesting first opinions! But it's not the pinnacle of intellectual thought.