|P is for Practical|
First, your 'O' doesn't seem very 'H' to me. But getting beyond that, you state "A threaded setup is vital for Perlmonks..." Vital? Really? This site has had tens of thousands of unique visitors, thousands of semi-regular users, hundreds of regulars, and has seen over 560000 posts over the course of five years. Among its regulars, you'll find authors of Perl and other computer-related books, professional programmers, authors and maintainers of Perl modules, Perl language developers, hobbyists, students, and teachers. Some users have produced thousands of posts. The site is among the top Google hits for "Perl". It has a section in Wikipedia. "PerlMonks" as a Google search term yields 259,000 hits. There is an answers.com entry on PerlMonks.
What is my point? My point is "vital" implies that a lack of this 'vital' component would induce failure. The site has thrived, so clearly the components vital to its flourishing existence are present.
As for "threaded setup", what do you think this discussion is, a disorganized bunch of nodes? No, it's a discussion thread. And if you want to see an overview of threads, you can look at Recently Active Threads (there's a link to that at the top righthand region of your screen).
If you dislike the look of the site, you're in luck. You can produce your own CSS attributes to customize the aesthetics and arrangement of pages here. There are other customizations available under your user settings. And there's always the Free Nodelet. And let's not forget the fact that there are RSS feeds available, and guess what; they're threaded. You can also get XML tickers for the site, and one of them offers a threaded view.
If you'd like to join us please do, and enjoy. But if you feel that participation here won't be a pleasing and enjoyable experience for you, go ahead and do what you feel is best for maximizing your own Perl experience. Start a site designed around your ideals, or join pmdev to help us improve your percieved deficiencies here, or hang out on Usenet.