I've visited a few communities quite a while ago, and I've found a common trait of those that didn't devolve into a cult: They were outward-oriented right from

I've visited a few communities quite a while ago, and I've found a common trait of those that didn't devolve into a cult: They were outward-oriented right from the beginning: Volunteering for various purposes, engaged in the local communities around etc. - things that made steady social contacts with the outside world a necessity. These communities usually also had less problems with gaining new people once the founding generation got a bit older. It's the same as with normal individuals, actually: The more the individual traits make one prefer solitude (like introversion or social anxiety), the more it is mandatory to maintain steady contact with others, otherwise the own comport zone steadily shrinks further.