To each generation their own Zone.
So don't worry about my reports of the Zone's demise. It's mostly dramatic effect to get people to think about civility, which IMHO is slowly being strangled by vulgarity, profanity & rudeness, not just in the zone, but almost everywhere.
I do discern your meaning, and I think the occasional mock-obituaries do serve as a reminder. I have an additional reaction to it because of my obvious affection for the "deceased". It's in that regard that it's a bit creepy.
Your comments about the circulation of membership really point to a strength of the community as an entity in its own right: It's self-renewing, like an organism replacing its cells. The change may, over time, affect the shape or to some degree the nature of the community or organism, but in both cases their "DNA" maintains the integrity of each as a concept. A living organism can't replace enough cells over the course of its lifetime to become another species of organism, and I think the same should be true of communities with high structural integrity, like the Zone.
Consider the theoretical possibility that, because it's just digital data, the HabitableZone could potentially be immortal. As long as the data gets copied from server to server (or whatever the equivalent may be in the distant future), there is no theoretical limit to the lifetime of a virtual community like this. Future historians and anthropologists would have a continuous record of what people have been thinking, going back however many years, decades, century, etc. the record has been maintained. Your cut-and-paste wit may become trapped in digital amber for all eternity and admired by beings we'd scarcely recognize as our descendents.
Ponder that, and look on these works not with despair but with hope, ye mighty...whatever ye are. Arrr arrr...