There's a sucker born every minute.
Back in my early 20s i was nearly part of such a scheme though it was not a total pyramid scheme.
It was about selling insurances on comission.. the guys were pushing aggressively to call everybody we have ever met and had the phone number for to arrange a meeting to talk about these insurances. The courses where you learned to sell them were pretty basic (you just basically learned some catchphrases and how to navigate/avoid tricky questions) but you had to pay for them.
You could earn much money if you sold many insurances but sooner or later your contact list would dry up and you'd be left out cold.
I even had a friend who left her job to pursue this "career" and after a few months after her savings were gone she thankfully wisened up and returned to her job (fortunately they took her back).
To this date i can pretty much see through bullshit like that but it's really not hard. Those people prey on the gullible and lazy to rip off their money.. it's even partway in the name of this scam!