This is the problem. And when the humans are politicians, or influenced or controlled by politicians, it's even worse. I proposed letting private entities, banks, commodity depositories, or anyone issue their own currencies and, even though each one might take years, or even decades, to develop enough of a reputation, if they really managed the currency carefully enough to develop a following, such currencies would have the tightest controls of all -- verrry hard-earned reputations and competition. Just musing. Wuddya think?
Private currency has been done in the US before, although it was more like a license than the actually ability to print money. The problem is that the all-important reputation is diluted as you move spatially away from the issuing bank. While this is less of a problem these days than say even 20 years ago, multiple currencies always injects a higher level of uncertainty into a transaction, especially if that transaction may span long periods of time (e.g., a 30-year mortgage). Personally, I’d be real nervous about giving a private entity the right to issue their own currencies.