The thing is, a lot of people just assume they must simply be doing good business. The continued existence of the economically impossible entity is, to many, proof not only of its solvency, but also of it's quality as a financial partner.
Most people don't look any further than that. Obviously, a large number do look further than that, and many, many people would never take the bait. But don't underestimate the number of people, even well resourced people, who would fall for this sort of scheme.