The suburbs are just another part of tax cuts for the rich. They're subsidized by the tax money from more dense parts of the city, which tend to be more poor (and usually filled with ethnicities other than white people - hence the term White Flight).

Singke family homes with big grassy lawns and McDonald's parking lots bring in less tax revenue and cost more money in city services per square foot of land than apartment buildings, being a net drain on the budget. So, there are higher taxes on the poor so that the wealthy suburbanites don't have to see them.