Being small definitely has its pros and cons, but consider that Singapore is a City-State in the same size class as Chicago (by Area, and actually a bit bigger)

Being small definitely has its pros and cons, but consider that Singapore is a City-State in the same size class as Chicago (by Area, and actually a bit bigger) and the same population class as say Colorado or Norway (5 millionish give or take) and only one tier of government, the National tier. They definitely lack natural resources and their tax base is that of a small country, but they don't have the usual 2-3 tiers of administrative overhead, the government is closer to the authoritarian end and any large capital projects they do undertake are largely going to benefit everyone to some degree simply because of how tight the nation is. Also being a nation that is one city does wonders for focusing on the habitability of that one city, and there's no other cities to compete for tax dollars there.