The Iranian dissidents appear to lack any kind of formal organization, which is both a strength and a weakness. It is a strength in that the regime can’t decapitate the movement with a few arrests; it is a weakness because the movement doesn’t know how to get to Point B from Point A. Organization can do that for you. Just ask the Bolsheviks.
As I have noted previously, the regime will survive as long as it remains united. So far, it mostly has, but there are reports that a few cracks are showing. How can the movement exploit those cracks?
The most obvious opportunity to terminate the regime will come when the Supreme Leader dies. In the shorter run, it would probably take an act of extreme, stupid brutality on the part of the security forces that mobilizes all decent opinion against the regime. We’re not quite there yet.
One thing is for sure: the regime no longer has any legitimacy in the eyes of anyone but its leaders.