I think I have seen the same argument about anime conventions. The idea is that a trend starts with a small group of passionate people, as things get bigger and more popular, followers arrive. Followers are not really passionate, they just jump on the bandwagon, but will leave and jump on another bandwagon as the thing gets less trendy. With the followers come people who will try to profit on them since they represent a sizable market. Among the "exploiters" are former members of the original group, who see a find a way to monetize their passion, taking advantage of their deep knowledge of the field.

So the idea that "people start to profit and the game is over" is mostly right, but the dynamic is more complex than just having a small number of people ruining it from everyone else.

And it is not all bad. While the community is less genuine, it is also more productive, if anything, just from the sheer numbers.