Some powerful economic and historical arguments here, and what governments could do to defeat Bitcoin...
http://moraluniversal.com/en/why-bitcoin-cannot-win/"Money is the product of society, just as Bitcoin is the product of a society of computers. Money needs the greatest human network to succeed, just as the Bitcoin blockchain needs the greatest computer consensus. This network and consensus, however imperfect, is ultimately provided by the state in modern societies, just as it was the case in the many cases of recoinage and remonetization throughout history. For as long as we have states that strong and accepted by people, for better or worse, Bitcoin will remain a substitute currency."
I'm goin' get a fresh cup of coffee now, then read the kindly linked article.
I'm pretty sure that all extinct currencies were once based upon their then modern society, e.g., the Romans weren't using nor accepting fish bones or seashells to or for trade. That said, what ever argument that's presented, US dollars, et al., could easily be added to the list of why--cannot-win.
EDIT: Read it.
The author also wrote:
Have you sold it to the NSA? At what price?