That's why I said that anyone reaching even 8,000 posts is somewhat dubious: interests shift with time. Much as we'd love to have NDK fans that are dedicated for life, the reality is that many people will eventually stop coming to NDK for one reason or another. Maybe it's because they've gone off to college, moved away because of work, started a family and don't have much free time, or just got tired of anime after a while. Whatever the reason, most convention attendees will eventually move on.
And because the NDK Forum is, of course, an extension of NDK, if someone moves on from NDK, it's most likely that they'll stop frequenting the NDK Forum. Or, at least, significantly reduce the time they spend here. So even for someone to post 2,000 posts a year (which is extremely rare), they must also keep up that momentum for a period of four years. If their momentum wanes, then it'll take five, six years--or longer. The fact is that most people, regardless of their hobby, don't often stay that impassioned about it for that long.
Now there are some places where I would expect people to reach into the tens of thousands of posts over the years--specifically those that appeal to broader subjects. For example, car forums. Or technology forums. Or heck, even general anime forums. The NDK Forum, though, is perhaps a bit too specific to hold many people's interest for that long.
Now don't get me wrong--I'd love for someone to prove me wrong. We certainly have some people that aren't going quite so fast as 2,000 posts but also show no signs of slowing. They may eventually reach 8,000 posts and that's great. But with the reality of something like NDK and its corresponding forum, I don't see many people reaching that point, if any.
Frankly, it would be hard for me to say I'll ever reach 8,000 posts. It's taken me about four years of steady activity to reach 2,500 posts. At this rate, it'd take me another eight years to hit 8,000 posts. I have no idea what my life is going to be like eight years from now, though, or whether NDK will be a part of it at that point--life is too unpredictable to say "yes, I'll absolutely still be doing what I'm doing now eight years from now."