- Mark Twain
If your currency isn't a liquid consumable good (like say tide detergent - look it up) or isn't backed by a nation state, it will get crushed as soon as it becomes popular enough.
Do you honestly think governments around the world are just going to stand around while people start ditching their currency systems?
No, they'll shut you down through violent, economic or legal means, and one way or another every alternative fiat currency goes down. Yes, I went there. Bitcoin is a fiat currency, it is something without any intrinsic value (unlike say copper), and is only valuable so long as the people controlling the computation (computational fiat) say it is, and others demand it.
Some will claim that Bitcoin is decentralized. I'll counter claim that it appears to be in theory, but in reality it really isn't.
If I were to shut down every bitcoin exchange (either through extreme legal, violent or economic means), I'd easily kill bitcoin overnight, mostly through destroying trust and inciting fear in adopters than from actually stopping exchange.
And if you don't believe governments are capable of this, you seriously have to read some more history. Governments are extremely dangerous, especially when it comes to economic control of scarce resources.
Do not underestimate them.
That's not to say that governments are inherently bad, but merely that they act in their own interests, and that if you are on the wrong side of their interests, the magnitude of their power, and the size of the prizes that are at stake, will probably end up with you being dead (most revolutions fail).
At the end of the day the guy with the nuke makes the rules.
Let's just hope he isn't too psychopathic.