I think the what a lot of people don't realize about ponzi schemes or pyramid schemes, or scams in general, is they don't rely purely or necessarily on fooling the 'victim'. Very often greed is enough of a motivator.
I've experienced at least one really big country-spanning pyramid scheme where lots of people participated, completely aware that it was a pyramid scheme. They just figured they'd be able to 'get out' before the thing would collapse. Obviously that often didn't work out...