How has a gross devaluation of all currencies occured? It hasn't.
Japan has been running defecits for over 20 years and still no devaluation of their currency. Near 0 interest rates for as long as I can remember and still no devaluation.
You cant ignore facts because they dont suit the argument.
the fact is that the US will only default if it CHOOSES to. Japan will only default if it CHOOSES to. Euro countries have no choice. they are forced to default.
Governments are not like households. They do not have financial constraints (unless forced upon them in the ways I described above).