There are some people that are exactly like you describe them and just risk because of the greed even though they understand that they can lose money, but there are still people that don't know how scam looks like or what is ponzi, no matter how unbeliveable that sounds to most of us.
There is also a lot of crypto noobs, who don't know much about crypto and Bitcoin, and it is very easy to mislead them. For example, I was contacted a few times from some freelancers, where they were promised payment in very strange ways. and it was a little complicated to explain to them that they will be deceived.
Plus, everyone heard about mining and some profit possibility from there. Some guy made money from crypto... it is very difficult for noobs to understand all things here.