I used to be able to get $3 breakfast and $5 lunch (ok, tipping rounds those up, but the base price is there) at nearly any Coney Island in the Detroit metro. It's not about richness or zoning, it's all about population density and disposable income. People in the US are poorer than we used to be, so restaurants only target the rich. US cities are remarkably fluffy and often less dense than suburbs in other countries. It's that simple.