I have been a part of and creating online communities for 20 years now and there is not going to be anything like HN for "normal people" anytime soon.
The reason HN works is because we are all in the same area and somewhat experts (or trying to be). The problem is that NO OTHER community is online nearly 100% of the time. So there is no writer HN, no science HN, the only thing that comes close is Reddit or 4chan because those are kids, who are also online 24/7.
Real people are in the real world, only techies and kids live online.