A shorter version of how I understood it:
There are people who love creating X.
There are people who admire X. Not being creators, their love of X manifests by supporting the creators: socially or otherwise.
Sometimes a cool community appears as a result.
There are many people who want the "cool" part, but don't intrinsically care about X. They join the group, but they complain that the X is too X. (What they really want is something 99% mainstream, with a small flavor of X, pretending to be the original X-centered community.)
Unless actively fought against, these people soon become a majority in the community, because the population contains much more people who want to be cool than people who love X. This creates a tension between the old fans and the new fans.
Finally someone sees the real dynamics of the group, and provides the masses exactly what they want (something 99% mainstream, with a small flavor of X, pretending to be X), in exchange for fame and money. Now there is a tension between the old creators + fans and the new creators + fans.
The old creators + fans complain that the community does not care about X anymore, but they are a minority, so they gradually retire from the community. (If they try an open conflict, they lose.)
In the absence of people who care about X, the community loses what made it unique. It is not cool anymore. Everyone is disappointed... except for the new creators, who easily move to another community ready to be exploited.
What can be done to prevent this?
Create costly barriers to entry; don't let the "fake fans" in. -- Problem: You give up the resources that even the "fake fans" would bring. Also, by being less famous, even the people who care about X may not find you.
Keep a limit on the number of "fake fans". (Author suggests that 6:1 ratio of "fake fans" to "true fans" is optimal; 10:1 is too much to handle.) -- Problem: The old members would have to consciously understand the strategy and agree on it. Also, it's difficult to regulate the "fake fans", because they come in waves.
Recognize the "fake creators" and eject them. -- Problem: Impossible. Geeks are famously bad at excluding. Also, at that moment the geeks will already be a minority in their own community; they may get steamrolled by the fans of a "fake creator".
Accept this life-cycle as a reality, and when things start doing downhill, be ready to quit and start a new hardcore-X community. -- Problem: Some old members will feel strongly about their old identity. Also, still a waste of resources.
Accept the "fake fans" as a reality, and create also what they want in exchange for their resources. (Still try to eject people who create only for the "fake fans".)
What can be done to prevent this?
Why do you think this should be prevented? "Accept this life-cycle as a reality" seems like a reasonable approach. The "old members" can keep their identity if it's really tied to hardcore-X. Or they can sit on their porches and grumble about kids these days :-)
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