Thomas Paine wrote that the precious metal system only worked because no one could create more of them, despite centuries of trying. Ole "OG T-Paine" and his Founding Father friends didn't know about the potential to go to space and lasso an asteroid chockablock with these precious metals, but with 2021's NASA being less competent than 1969's NASA, I'm sure we'll be long gone before we start sending out the space cowboys to do asteroid roundups. So long as gold/silver have uses besides just being currency, I think they could survive as a currency system even if some space cowboys brought back a giant nugget of it, as from the gold advocates I've learned that gold has remained remarkably stable in value over the centuries, despite the various gold rushes and continued introduction of newly-mined gold into circulation.