Sounds easy huh? Here's the problem...
If you print more money, demand > supply --> US$ currency deflation (perhaps A$0.01 for US$10) --> meaning it'll still take just as long to pay the debt back
In the mean time you have just created an inflation problem since your China imports and Australian thermal coal imports oh and Japanese and German car imports suddenly cost a lot more... hyperinflation, just like Zimbabwe. Before we know it Obama will impose martial law and might start shooting oppositions' wives.
And... in the meantime since your currency is so worthless you'll never be able to afford to go to any country on a holiday. Indonesians will be going to get America for cheap foot massages too... and tip them used chewing gum, since Americans generally would not be able to afford Made in Indonesia chewing gum anymore given such a worthless currency.
Though if that happened, the US can always change tactics and be a basket case third-world country and start exporting stuff and doing slave labour. All the countries revert back to that at some point.
Reality is they obviously do print money, but only in small doses. Try print an amount equivalent to your debt, your currency won't be worth my effort in typing the last word in this sentence.
I am far more optimistic than that on the USA.
1. Their debts are priced especially government debt exclusively in US dollars.
IF you look at countries that have suffered hyperinflation when paying off debts they are using their own currency to pay off a debt in another currency. Look at weimar Germany, they printed out tonnes of marks only to see them right back in their own economy pushing down their marks value and increasing the amount of debt valued in marks so needing to back 2 trucks up next time then three then four then five etc etc to pay the ever increasing debt priced in marks.
The USA has a debt valued in US dollars whatever they print it will still be in US dollars. Of course it is the end of the US currency being the world currency but I think this is a given anyway.
2. They are an industrial powerhouse.
per person compared to nearly any other nation they make more stuff per person. Whether it be tonnes of steel, highways, computer chips, whatever believe it or not they make an awfull lot of stuff including food. Productivity in the long term drives a nations prosperity vs other nations. USA is one of the most productive in the world, even if it is a bit harsh on its worker citizens to achieve this.
3. Poor countries are just poor its not just about debt / currency value, does not matter if they have to pay with a million US dollars for a burger or 5 they are still a wealthy nation relatively speaking.
Why countries are really poor is they have no roads, power, natural endowment (food minerals etc etc. In the long term a poor country either has to develop like China has started post a brief hiatas after the farmer revolution, now they have for the last 2 decades developed. Invested in eduation, infrastructure, research and even land improvement while countries like Australia hand out cash and build school halls, hand out free insulation then wonder why we are falling behind...
There are other reasons but I am conscious of my habit to create wall of texts at every opportunity... I will say this though, Swan was quizzed the other day why it is we continue to slide on the productivity stakes v countries like the USA when it was one of his mantras at the 07 election, the libs dropped the ball on productivity.
I agree the libs did not do the hard yards on infrastructure which in fairness to Labor they have historically championed, Sydney Harbour bridge; Lang, Snowy River Hydroelectric Scheme ; Chifley
The current labor government seems to think a broadband scheme allowing us to download porn quicker and costing 5 times in todays dollars the cost of the snowy river hydro, that scheme which provides water security for around 40% of our food production is worth comparing!
The USA will be OK in the long run I am more worried about Australia... If we don't wake up and start developing we are the ones who are going to be left behind. A strong terms of trade is masking our otherwise weak as **** economy in my opinion. I know when the terms of trade revert back to long term numbers what the likes of Swan will say too. An unprecedented and unexpected shift in the terms of trade when any economist, hell even mining bosses are warning them they cannot drop the ball on the greater economy ex mining.
Edited: spacing and formatting