A scheme where each recruiter signs up six people runs out of planet by round thirteen

A pyramid scheme pays existing members for recruiting new ones rather than for selling any real product, which means it depends on an ever-expanding base of new recruits just to keep paying out. If each member recruits only six others, by the twelfth layer you'd already need 2.2 billion participants, and the thirteenth layer would require more recruits than there are people on Earth. The exponential math guarantees collapse; only early joiners near the top ever profit.

— Wikipedia contributors, Pyramid scheme — Fraudulent recruitment-based business model