"The fundamental law of capitalism is: When workers have more money, businesses have more customers. Which makes middle-class consumers — not rich businesspeople — the true job creators. A thriving middle class isn't a consequence of growth — which is what the trickle-down advocates would tell you. A thriving middle class is the source of growth and prosperity in capitalist economies.
Our economy has changed, lest you think that the minimum wage is for teenagers. The average age of a fast-food worker is 28. And minimum wage jobs aren't confined to a small corner of the economy. By 2040, it is estimated that 48 percent of all American jobs will be low-wage service jobs. We need to reckon with this. What will our economy be like when it's dominated by low paying service jobs? What proportion of the population do we want to live on food stamps? 50 percent? Does this matter? Should we care?"
http://billmoyers.com/2014/09/11/a-wealthy-capitalist-on-why-money-doesnt-trickle-down/