I think it can be satisfactory under certain conditions. City-scale works because people can vote with their feet (the binary Keynesian beauty contest has an escape hatch), diversity is somewhat limited, and there is somewhat more accountability (the mayor lives in the same city, walks the same streets as its inhabitants).

But it's certainly not democratic at the scale of a country-continent such as the USA. Their citizens don't have the freedom to vote with their feet (even less than other countries due to the unique tax on citizenship that follows them around the world), and city/countryside people have opposing opinions on many important issues.