Forums with good moderation solve those problems. A nice example is rpg.net.
Traditional linear forums are still the best format for in-depth discussion, IMO. Threads actually stick around for more than a day or two. Just compare gamedev.net to /r/gamedev.
It felt like there was an inflection point around '96 or '97 when Usenet really dried up and web-based forums became the most common way to discuss things on the Internet. I blamed it on Slashdot at the time but I think it was inevitable as more and more people got on the Internet.
I really feel like we lost something though. Newsreaders provided a much better way to engage in the kinds of conversations that people have on place like HN or even Reddit. To this day I don't know of any web forums that offer the conveniences of newsreaders like tin or slrn. I miss killfiles (and plonking!) and really, really, really well-maintained FAQs on just about anything.
I'm not sure how much of my Usenet nostalgia is just remembering the good stuff. It may not have been as great as I remember, but it sure seemed like it at the time. I learned so much from it, from so many people in so many different newsgroups. Maybe that's what places like HN are to larval hackers today.
Well, discussion forums incite somewhat different types of posts than news sites (which are the primary case for peer-vote moderation for whatever reason). And top-down moderation is also quite different. So yeah, I agree those don't have that specific problem.
Traditional linear forums are still the best format for in-depth discussion, IMO. Threads actually stick around for more than a day or two. Just compare gamedev.net to /r/gamedev.