The hell they don't. They pay sales, gas, and property taxes (in their rent). It adds up to an average of over $9,000 per year for a family of four.
And you would choke if you saw the taxes my wife and I paid as two educated professionals before my wife quite work to be a stay at home mother. I kid you not, I paid more in income taxes in 2006 than my mother earns, whom I support.
I would love to only pay $9000 a year!