However, by that measure bitcoin has already achieved success. The bitcoin network currently mediates between 50 and 60 thousand transactions every day, transferring an estimated 70 million USD every day.
As far as bootstrapped nascent currency experiments go, bitcoin should certainly fulfill many criteria for "success" already.
Curioulsy the number of transactions per day and their total BTC volume have increased very little, or not at all, since September last year. So, either commercial e-payments are a small fraction of those numbers, or they are not increasing (and their USD volume is actually decreasing, since the BTC price has fallen considerably in that period).
Has not grown since a date arbitrarily chosen by you? (Or perhaps deliberately chosen by you in order to make a point?) Well, I guess it's a failure, then...
Facts:
(1) Bitcoin is moving large sums around every day.
(2) It is very useful for "many" (tens of thousands/hundreds of thousands?) people.
(3) The usage has increased - maybe not steadily, but consistently.
I guess it's OK to be skeptical, and it's quite correct to be wary of speculating in the bitcoin price. But to claim it is anything other than a resounding success is disingenuous. It's already successful and is making life easier for a large number of people.
And since you are from Brazil, let me ask you: have you ever tried receiving payments from abroad? It is exceptionally expensive and time-consuming to send money to Brazil from a foreign country by regular banking channels. Bitcoin facilitates this tremendously, and is used by many. Is that not enough to be considered successful?