The American Economy and Pyramid Schemes
1). First of all there must be people interested in actually buying what Americans make. There are, of course -- but not enough, apparently, which is one of the reasons for the recession. The American economy cannot survive by everybody selling to everybody; something must be produced.
2). Second, one must not build one's "prosperity" on the sand of the "greater fool" theory, like the internet or housing bubble. Real estate prices, as well as internet companies' stock prices, were built on people buying something one knows is terribly overpriced with the expectation that someone else will buy from you.
3). One should, as far as possible, live within one's means (yeah, I know, I know -- none of us do, but you know what I mean...) Do not spend your money on shiny gadgets in order to impress people if it gets you into debt. It is hard enough to pay legitimate debt (like mortages or bills for food, medicine, education, etc.) without adding to it that extra payment for the hot car or big-screen TV you really want.
The list could be extended. But does this seem to have a familiar ring? Why, yes -- this is precisely the MLM business model. The weaknesses and problems of the American economy (or of any advanced economy): overspending, buying overpriced useless stuff so that others will buy it knowing it is overpriced useless stuff but hoping others will buy from them, a proportion of about 1:100 between the number of salesmen in the MLM in relation to the number of people who actually produce their product, etc., etc. -- is what MLMs are all about.
Even if there was no problem at all with MLMs legally or morally speaking, they would be economically worthless.