Are MLM (Multi-level marketing) companies legit?

people that want to buy something go to store and buy it. they wont wait around for someone to come to the door. or buy stuff from mlm dealers at fairs. i go to a lot of fairs and will see multiple watkins exhibits at fairs selling spices and other food coloring and flavor products that you can buy for fraction of the price at grocery stores. i don't see anyone buying the Watkins products at the fair exhibits. there was a glacial milk mineral product sold that way by mail and i would be getting the dead doctors don't lie audio tapes in the mail from a large number of people from multiple states trying to sell the product. that company made their money by selling the audio tapes to people that hoped to make money selling the glacial milk mail order. the multi level marketing door to door or through the mail selling products make money off the poor those least able to afford the money those companies sell. lot of out of work people pay the last of their money to the mlm companies hoping to make a living only to find they been conned out of the last of their money. now they are out on the streets homeless and starving.