In the freebanking era that the US had (before the FED was founded) every bank emmitet their own dollar. And, of course, there were banks over-issuing and bank runs left people without their assets. But that was before we had free flow of information and the internet. In todays world you can monitor and trade stablecoins, market cap, exchange rates in a freebanking system in sub-seconds. Any erosion in trust will immediately result in price fluctuations. We need a digital freebanking era, and it is a shame the genius act fell through. Exporting the dollar to people without access to banking would benefit the US (but I get that it currently mostly benefits trumps family).
But: Are you sure that Tether is actually backed by USD? It certainly isn't free information.