Being in the 18th century had nothing to do with the system they set up. It was set up that way so that wealth would not be under the central control of the State, and so the currency of the nation would actually have intrinsic value. That same system is just as relevant and possible today, as then. If sound money were an 18th century ideal, why would the Chinese be busy buying gold, and not releasing figures as to how much they actually own?