You might think that people without extravagant amounts of disposable income would be inclined to do serious research to make sure they are not wasting money, but, unfortunately, many people have no clue how to do serious research, and therefore are often subject to the same scams as the rich. Being less affluent is no guarantee of sagacity. This is borne out by the fact that many people without massive amounts of disposable income still buy into (literally and figuratively) various audio frauds.
I did not say that all rich people are unintelligent. However, people born with a silver spoon in their mouths can be as intellectually lazy as they want to be. After all, they need not bother to figure out anything, as they can pay someone else to do everything for them.
And, of course, those who single-mindedly devote themselves to making money haven't the time or inclination to figure other things out. There are, after all, 24 hours in a day for everyone, and time spent on one pursuit is time not spent on another. Learning how to examine things carefully is something that takes time to learn, and those who do not take the time or effort for it never learn it.
If you want to have a truly frightening experience, take an introductory logic or critical thinking class at your local college. What is frightening is how many people are incapable of adequately dealing with the subject.