Revolutions often follow failed or half-hearted attempts at reform or concessions by weakening regimes under the influence of foreign powers. One of the clearest modern examples of this is the overthrow of the Shah of Iran after his attempt to impose from above wide-ranging modernization. The westernizing reforms urged by the US threatened traditional elites. The revolution originally included a broad coalition of groups, but after the Shah fled, it was the best-armed and organized elements, the religious fundamentalists following the Ayatollah Khomeini, who seized and kept power by quite ruthless methods.
This follows a pattern that goes back through the other "great social revolutions" in China, Russia and France studied by the sociologists of revolution, including Skocpol, Goldstein, and the Tilleys. One could certainly argue, as does Hartmann, that events in Libya, Egypt and other Arab countries that have gone through partial or incomplete revolutions follow the same pattern.
1. Wealth without work. 2. Pleasure without conscience. 3. Knowledge without character. 4. Business without ethics. 5. Science without humanity. 6. Religion without sacrifice. 7. Politics without principle.