"Also, to show the ulltimate silliness of your reasoning, imagine tha tthere were one world governement, and very rapid communication and movement of goods, services, information and people around the world.
Would they have to export to Mars to create any economic value
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Economic value is an abstraction. Ultimately, we rely on original creation of value - production of food and other materials and value-added modifications to those commodities. The simple fact is that a closed economic system cannot exist without creating that original economic value. At the end of the day, we need to eat. If someone is not growing the food we're selling, everyone starves.
The upshot is is that we collectively produce an excess of value - we extract more from our environment than we consume. This excess of value creates a market for luxuries like a closet full of clothing, two or more cars per household, or any number of consumer goods in ours homes.
Now if a rural community has no agiculture, no industry, and no exogenous source of revenue, there is nothing to multiply - the car dealer does not add value to the local economy, but rather extracts value.
At the end of the day. someone actually has to produce something for value to be created. I think that's something a lot of people in lower Manhattan are learning now.