Why is this so unusual? Because in most Middle East states, power grows out of the barrel of a gun and out of a barrel of oil — and that combination is very hard to overthrow.
Oil is a key reason that democracy has had such a hard time emerging in the Middle East, except in one of the few states with no oil: Lebanon. Because once kings and dictators seize power, they can entrench themselves, not only by imprisoning their foes and killing their enemies, but by buying off their people and using oil wealth to build huge internal security apparatuses.
There is only one precedent for an oil-funded autocrat in the Middle East being toppled by a people’s revolution, not by a military coup, and that was in … Iran.