Yes paper currency will be around for 20+ years, probably more. However the US government DOES want a decline of the dollar, though not a death. Its enormous debts are denominated in dollars so it is in the interests of the US government to see a decline in the dollar because this means a decline of the real value of its debts. The pound lost 25% of its value in 2008 and this was praised by many in "The City". Paper currencies are in a "race to the bottom".
Ahh this makes sense... I guess the question is what will big Government turn to after they devalue the dollar? How will they collect taxes, and in what form will the average man be paid? I don't like the idea of the government collecting taxes from my bitcoins, but I also recognize the need for a tax paying society in order to function.
Devalued simply means worth less not worthless. They will pay people and collect taxes just like they do now. It just might be that minimum wage is $48 an hour a Combo meal at burger king costs $60.00 and a college education (state college 4 years) is $1.2 million.