What triggers revolutions

I want to call your attention to an article called "When Change Is Not Enough: The Seven Steps To Revolution":

Here's an excerpt:

Progressive modern democracies run on mutual trust between classes and a shared vision of the common good that binds widely disparate groups together. Now, we're also about to re-learn the historical lesson that liberals like flat hierarchies, racial and religious tolerance, and easy class mobility not because we're soft-headed and soft-hearted — but because, unlike short-sighted conservatives, we understand that tight social cohesion is our most reliable and powerful bulwark against the kinds of revolutions that bring down great economies, nations and cultures... [T]he stage for revolution [has historically been] set when the upper classes broke faith with society's other groups, and began to openly prey on them in ways that threatened their very future. Not surprisingly, the other groups soon united, took up arms, and
rebelled.

And here we are again: Conservative policies have opened the wealth gap to Depression levels; put workers at the total mercy of their employers; and deprived the working and middle classes of access to education, home ownership, health care, capital, legal redress, and their expectations of a better future for their kids. You can only get away with blaming this on gays and Mexicans for so long before people get wise to the game. And as the primaries are making clear: Americans are getting wise.

Our current plutocratic nobility may soon face the same stark choice its English, French, and Russian predecessors did. They can keep their heads and take proactive steps to close the gap between themselves and the common folk... Or they can keep insisting stubbornly on their elite prerogatives, until that gap widens to the point where the revolution comes — and they will lose their heads entirely.

I wonder if revolution is even possible any more, however. There are such sophisticated methods of crowd control these days as well as surveillance methods. I wonder if it's possible for there to be a successful uprising.