[afiori]

The amount of money/value/richness in the world is not constant.

Suppose we all lived on an island in a completely stable economy valued somehow at 1 trillion dollars.

Then imagine that a dozen or so explorers went to another island and started a completely independent economy that (after some centuries) gets also valued at 1 trillion dollars.

The latter billion dollar was created at the meager cost of a boat and the life work of some people.

This is a horrible analogy for anything that ever happened, but it is something that could possibly happen.