I've been on this forum a little over a year. I'm interested in the low-end vintage bikes because I can afford to buy them, and also because they are easier to find, as someone stated previously. Maybe a little too affordable and easy to find, because now I have more bikes than I can handle.
The other reason is that I need to learn and practice basic and advanced bike maintenance on less-valuable bikes before I tackle the high-end dream machines often pictured on this forum. I'll never get tired of reading the "how-to" threads, or the valuation threads, or advice threads.
But I enjoy seeing the high-end bikes just as much. I never heard of any of them before joining this forum, and even after a year here, I'm still seeing bike names new to me. This forum is the single most important resource I have for learning about my new-found hobby and interest, and I hope I'll acquire enough expertise such that I can be a resource for others here as well someday.
As it is now, I spend too much time on this forum myself, and not enough time working on the bikes overflowing my garage, much less out on a pleasure ride. So I wouldn't be at all surprised if the older regular posters have simply cut their online time in favor of increasing their riding time.