"Look what we saw when we passed be when we immigrated from the old country to Pignuts Arkansas" said no one ever.
Volumes indeed. Of cash.
Big cities are big because they're economic engines and thus people flock to them. Those whose place as generators (like in the Midwest, Rust Belt) are in the past (as manufacturing declined), shrink.
Those - basically coastal - that are adaptable money hubs are restricted in growth only by lack of real estate to expand in. That's why you have buildings in NYC in which more money flows through one single floor in a month than does through entire counties in Red States in a year.
That the more economically sound ones tend to vote majority Democrat while the economically moribund ones tend to vote Republican doesn't require a calculator and GPS to figure out what the name of that tune is. Basic "New York, New York" vs "Tumbling Tumbleweeds" humming on that jukebox,,,