That's why we run a trade deficit (capital surplus). Many people can't move here, but they can send their money.
You understand that we're sending money out and other countries are sending goods in, right? Our national debt is now 5 point something of the budget and rising, not counting private bonds, such as mortgages etc. that are held by the Chinese and Japanese. And that consumer debt, acquired in the purchase of imported goods, is at an all time high.