It happened gradually. But wars usually put stress on the gold system. They caused the fault lines to slip, so to speak.

The US Dollar was the last major currency tied to gold and we finally severed that tie in 1972 when the Bretton Woods system ended.

And the reason it happened is that in order for prices to remain stable, we needed to be able to adjust the amount of money flowing in the economy to an extent greater than gold would allow.

> It requires government manipulation by price fixing, outright debasement and mechanisms like legal tender laws for worthless tokens to win out over a precious metal such as gold.

Yup! With the rate of economic growth outstripping the rate at which we could mine gold or spend new gold certificates into the economy, gold just simply wasn't going to cut it anymore as a stable basis for a currency. In order for markets to function smoothly, we needed a currency that could be actively managed.