They can also target exchanges outside of the country through bank seizures. They can't stop the rest of the world, but think of a) the influence that the US government, for example, has on the policies of other governments, and b) what would happen to the price of bitcoin if the legal bitcoin-related market of major countries were to disappear. As for cash, we can't go back to the stone age. Continued growth IMO requires fast, electronic payment solutions.
Maybe it's just me. I have no idea what average Joe will do, but considering what has happened in Cyprus and how many ordinary folks hate EU I would not underestimate them.
IMO events like "Cyprus" only affect speculators. I think average people want proven stores of value that are easy to transact in (both in terms of fiat/asset exchange and ease of use). At this point, bitcoin can't offer this.
The real problem re government is that if bitcoin does achieve significantly rising adoption levels, it won't be so thinly traded. It is at that point that it may receive unwanted attention. If the US government is afraid of something, it tends to squash it.
In this context, bitcoin may or may not achieve the mass appeal that would thrive despite government crackdown. Not so sure it will. I've seen it suggested here that drug prohibition is analogous to bitcoin prohibition -- crazy! Drug consumers don't have alternatives. Consumers have too many viable alternatives to bitcoin. The next question, then, is whether bitcoin can truly grow into more than its principal uses as a speculative vehicle for fiat, and currency for black market goods (drugs, gambling, etc).
So, not assuming either will happen, which comes first? A truly viable bitcoin economy? Or a government crackdown? I suppose that's the final question...
But file-sharing protocol is not an asset. People are not willing to pay for it. There is no market for money there -- I don't think it applies to bitcoin. I mean, who doesn't love free shit...
And living large in Ireland running everything out of a Big Slush Fund...
When the DOJ of Lower Manhattan shut it down in 5 minutes.
Pokers Star paid $731 million to settle with the US government.
http://www.forbes.com/sites/nathanvardi/2012/07/31/pokerstars-will-pay-547-million-to-settle-u-s-government-charges-and-buy-full-tilt-poker/
There is a non-trivial probability this is what happens to MtGox.
Yes, this specifically is one of the things in the back of my mind that colors my longterm outlook on bitcoin. If this were to happen, the centralization that Gox entails could cripple bitcoin.