The nations are not gathered in automatically. If God has promised to bless "all the families of the earth," he has promised to do so "through Abraham's seed" (Genesis 12:3, 22:18). Now we are Abraham's seed by faith, and the earth's families will be blessed only if we go to them with the gospel. That is God's plain purpose.
There are now businesses and entire industries that exist solely as a result of federal patronage. Profiting from government instead of earning profits in the economy, such businesses can continue to succeed even if they are squandering resources and making products that people wouldn't ordinarily buy.