Publius offers a less-than-idealistic take on the reform movement in Iran:
The Iranian economy is in very poor shape, and the regime is considered to be a contributing factor to the poor economy. [...] The election was the spark. But the ultimate cause (the dry forest that was susceptible to fire, if you will) was Iran's economic problems. It's more romantic, of course, to see the struggle in ideological terms as a fight for freedom and reform, etc. But it seems more like an economic fight to me.
It's a key difference between the Chinese and Iranian regimes. The Chinese regime also suppresses personal liberty. But, it is seen as useful to prosperity. China's economy has generally done pretty well lately. Iran's regime is not perceived that way.