David Hume showed why hoarding all the world's gold would eventually backfire

Hume argued in 1752 that if one country somehow accumulated most of the world's gold, its prices would rise so much that its exports would become too expensive to sell, while imports would look cheap by comparison, draining the gold straight back out again. This self-correcting flow of money across borders, now called the price-specie flow mechanism, became one of the first rigorous arguments against mercantilist policies that treated hoarding gold as the whole point of trade.

— David Hume, Of the Balance of Trade — Political Discourses, 1752