This is especially common in churches because in addition to having an existing trust relationship, in many more conservative denominations you also have a large population of women who are expected to be mothers first and working second but are also expected to be the frugal wife running the household like a small business (there are several scriptures like Proverbs 31 which mention this in contexts which make more sense if your household is a small farm & you're selling your surplus). Those pitches explicitly borrow from that tradition and they always refer to it as being a small business owner, which sounds a lot better than working part-time at Starbucks even if the latter tends to pay considerably better, and that's also appealing to the people who see working outside the home as being out in the world exposed to all kinds of dangers and temptations since you can tell yourself that you'll mostly sell to people you already know.

What tends to happen is that the first person who picks up some new scam does fairly well because there's no exact competition for whatever they're selling. They tell their friends, who are likely to join because they made an enviable amount of money, but returns drop off rapidly because most of the people who want whatever that company is selling already bought it from the first person (whose social network overlaps considerably) and at some point most of the money is coming from the people buying the initial inventory which will mostly sit in their garage.

The social dynamic also means that _nobody_ will ever admit that they lost money or made the equivalent of $2/hour even as they're giving away that unsold merchandise at baby showers for the next 5 years.

Cryptocurrencies have largely been the brilliant idea of capturing this dynamic for a different demographic (libertarian men).