Japan has a very high savings rate which (it seems) has cushioned the debt burden. But look at the American continental dollar, French assignat, German mark, Hungarian pengo, Zimbabwe dollar, Yugoslav dinar, Sprska dinar, Greek drachma, Chinese fabi, Armenian dram, and Turkmen manat. Currencies absolutely can die (or at least be revalued much lower). 

 *be revalued much lower. Like I said, Some homeless people live a long time intentionally destroying themselves.