Seriously, if you have an entire continent at your disposal, running an economy is easy. Likewise, after WW2 most of the the rest of the developed world was in a shambles, and the US was the only industrial economy that hadn't been bombed heavily. Unsurprisingly, a long period of great economic growth followed, in time with the Bretton Woods system but not necessarily because of it.
I'm very interested in monetary theory, but a lot of gold fans seem to attribute stability or growth to the use of gold rather than extremely favorable economic conditions. If you back and read the the Wealth of Nations, there's a very worthwhile (if long-winded) explanation by Smith of how hard currency can act as a limit upon economic growth, as well as being corruptible in its own right.
Which is why Australia has such a remarkably stable economy, right? Oh, wait... http://www.abc.net.au/news/linkableblob/3873450/thumbnail/je...
See http://www.abc.net.au/unleashed/3872646.html for context, and in particular the bit about "mad boom and bust cycles".
This itself is interesting: because Australia is an island continent, with few or no internal volcanoes or rift zones, the land is, literally, ancient, with many nutrients vital for ag production missing (one estimate I saw was that seeding land with an infinitesimal amount of iron would greatly increase production). Much productivity is due to windblown dust from the Indian subcontinent and south-east Asia. Even where irrigation is possible, evaporation causes accumulation of salts which degrade ag values. The first settlements in Sydney very nearly starved due to difficulties in producing sufficient food.
The paper money clearly does not respect ANY of these principles nowadays. The FED can print (and does) as much as they want to buy back toxic assets (remember the Krugman clown advising after the Net bubble in 2001 that we should create a housing bubble to stimulate the economy ? That really worked well for everyone, did it not?). The US Dollar is constantly losing value versus Gold since its parity was dropped for good in the 70s, and now you have such a galoping inflation than looking at movies 30 years ago make you feel old: then the bad guys were asking for "a million dollars" as something highly valuable/desirable, while nowadays if you do not cross the billion mark it is not considered as much anymore (Austin Powers made this very good point in a clever way).
Why do you think China is buying all the Gold it can currently to replace its stinky dollars?
Currency is based entirely on concensus. Anything (ivory, sheep, even bits of paper) could be currency; the only requirement is that there are people willing to use it as a basis for trade. In other words, it doesn't really matter if you don't believe in paper currency as long as everyone else does.