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.