This is the most curious part to me - neglecting your website for 10 years is pretty much unheard of in the web dev world! I've worked on some big websites that have seen 2 or 3 major iterations in that same time.. For their own sake, I hope this site gets a facelift very soon. Like I mentioned in another thread, RR is at risk of losing their userbase should a competitor site show up offering a modern UX.
The neglecting can very easily be explained, and is a bit more common than you may have seen. Most of my work has been overhauling older websites. Usually, someone has a passion, or notices a lack of a resource, and either builds the website themselves, or get someone they know to do it. Heck, they may even hire a team. In the end, it's built, it works, and the developer is no longer needed. At this point it can go 2 different ways, they either keep a developer on board for fixes, or enlist a community members' help. Regardless, this person turns into their go to guy. Since the website works, no reason to upgrade it....right? Time passes, everything still works. Once in a while there's an issue, but not often.
Given 5 years time, or in RR case 10, people change. The initial developer gets a new job, gets married, has a kid, etc. If it was a community member, their passion for web work may have died off. A whole bunch of new frameworks exist, and certain software had major improvements. The need to upgrade, or even overhaul(including new forum software), has come to mind. Well, with all the changes and time constraints it becomes a very difficult job. Especially if it's just one person. As you know what it's like being a developer, you know how long it can take. Database migration, integration, testing, and deploying. The time is even longer if the person doing it all has been out of the game for a while. Relearning can take some time!
Even a more modern website, whether custom or using frameworks, will take a while. So unless something has been in the works already, I doubt we will see a newer website popping up anytime soon. Seeing Mike's response earlier, it's much more likely RR will get it's overhaul before that happens! If we want it done right, we are going to have to accept that it'll "be done when it's done" Surely, we will have a form of advance warning before it goes live. Something to look forward to!