Earlier quoted context omitted.
I'm suggestioning that American stop subsidizing vast unpopulated areas of its country for the benefit of a subset of the country. Once the subsidies are deverted, the areas will naturally depopulate.
Subsidize? Maybe those vastly unpopulated areas of the country ought to stop feeding those 100 miles from the coast.
In reality, the situation is reversed. The US largest export, by FAR, is agriculture and meat, almost none of which comes from the coasts.
If you want to count GDP, do you really think that the trillions of dollars of bank profits from lower Manhattan are really as important to the economy of the US as the trillions of dollars of corn, soy beans, wheat, beef, pork, etc that's produced in the Midwest? The former is just redistribution of wealth, the latter is actually traded to other countries.
How bout all that energy produced in Oklahoma, North Dakota, Pennsylvania, West Virginia, and Texas? Do you think the US would miss it more than they'd miss the hundreds of billions of dollars spent in DC on mostly dubious military spending or on the thousands of silicon valley companies finding creative ways to serve tracking ads?
In reality, if the red states and blue states separated from each other, you'd have one nation with massive real exportable wealth divided by a small population, and another nation with mostly printed and worthless dollars backed by non exportable services, divided by a huge amount of people and their unfunded entitlements.