With an equal number of letters sent out in each generation, perhaps a thousand, these are the results. And, if the response rate is greater for a well crafted appeal, the profits increase rapidly. A chain letter sent by the originator is nothing more than an illegal business letter asking you to do something to contribute money to the initial sender. As you can see from the graph, the more people who respond, the greater the income to the originator. As you would expect, those who receive chain letters and follow the instructions rarely, if ever, profit from them.
Chain letters are merely carefully crafted business letters asking for contributions.
Not only that, they ask you to forward the chain letters so that you ask others for additional contributions to the originator. I hope this helps you better understand chain letters and how they actually do work.