You're thinking in Internet Time. In IRL Time, OWS has accomplished a great deal in terms of shifting the debate. No, the bankers haven't been sent to jail and students are still unemployed. Just yesterday, however, we had Newt Gingrich of all people saying that capitalism shouldn't benefit the few at the expense of the many, and that the reckless pursuit of profit at the expense of people is a perversion of capitalism. Were it not for OWS, we would never be hearing that (and certainly not from Newt).
We technorati tend to be pretty self-effacing, which is usually a good thing. When we ignore our real successes, however, we sell ourselves short and discourage future attempts to change things.
I agree, we're generally pretty bad at convincing people that we're right. We usually adopt the, "I know I'm right, who cares if this idiot agrees" attitude. That said, we've been very successful at empowering others to advance causes. We can acknowledge our failings without ignoring our successes.