As a political scientist, I scrunch my eyebrows a bit at the current crisis in the Middle East. It tickles my sensibilities in the wrong way: can one man setting himself on fire in Tunis really bring down a well-established regional system of government?
Obviously, the answer is "not on its own." More deeply, the answer is, frankly, "not at all." Generally speaking, the Realist school of political science sees events like the self-immolation in Tunis as minimally significant to the broader brushstrokes of geopolitics.
What I mean is this: many folks in many countries at many times (including much of the Middle East) have set themselves ablaze, gone on hunger strike, or otherwise protested for change, and gotten nowhere. To say that the "conditions were ripe" in the Middle East under-attributes the importance of the conditions themselves.
An historical example:
After the assassination of the Archduke Franz Ferdinand, tensions were high between the Austrians and Serbs. But the Austrians and Russians were largely ready to settle on a "March to Belgrade" by the Austrians, in which they'd simply hold the Serbian capital as the internal revolts were brought under control.
Two main factors led to World War I itself: offensive war methodology (the ubiquitous and profound belief that the best defense is a good offense), and Germany's border instability and desire to create buffer zones in Central and Western Europe.
Similarly, the election of Abraham Lincoln had ultimately little to do with the start of the Civil War. The Gulf of Tonkin incident had literally nothing to do with the American intervention in Vietnam.
Ultimately, all these events were caused by broad geopolitical factors that small, relatively random (in the scope of world politics) perturbations like a sacrificial protest cannot meaningfully change.
There will always be events that could lead to a crisis. Whether such a crisis emerges depends entirely on the geopolitical conditions going in. The Middle East is no different.
The reason for the current political instability is, ultimately, financial instability caused by decades of mismanaged central planning that led to sufficient dissatisfaction with the current regimes.
Oppression and suppression of alternative political groups is not a trivial point, but traditionally has not been enough in the past forty years of the Middle East to facilitate a popular change in government.
Ultimately, yes: the same geopolitical forces that drove the beginnings of the World Wars, the fall of the Soviet Union--these, too, drive the changes we're currently seeing in the Middle East.