Have We Misread The World? II

A reader writes:

My friends and I have been talking about this, and we have another, perhaps more convoluted theory.  That terrorist organizations and (more specifically) their leadership, are motivated by rational behavior more than religious zealotry.  Zealotry is just the weapon, used by rational top-tier actors like Bin Laden.  The biggest goal of leadership is to maintain their power and the influence of their organization.  Thus, the organization benefits if it:
1. Is seen as the underdog
2. Has a seemingly invincible foe onto which it directs rhetoric and violence
3. Carries the support of an indigenous population
4. Can convince others that its mission is righteous
Recall that much of the world rallied behind us after 9/11, people and governments and old stale friendships and even enemies were moved by the destruction that day.  And the immediate steps we took directly after to freeze assets and other strategic maneuvers hurt Al Qaeda greatly.  While Al Qaeda certainly scored a "victory" over us on 9/11, how would other, similarly spectacular victories shift the balance of power?  What would happen if they were to detonate a dirty bomb in a major US or European city, or carry multiple repeat victories?
The delicate balance would shift.  They would no longer be the underdog, the David taking on Goliath--it would be extremely hard to maintain that illusion.  They would be viewed as out of control and dangerous and brutal to the populations that currently support them. Their foe--the United States--would lose it's devilish, invincible nature, become beatable.  And their mission, viewed by the bulk of humanity, would be stained and less righteous.  The most recent example of this was the rejection of Al Qaeda by the Sunni minority in Iraq--they overstepped their bounds, lost the "liberator" illusion, and payed for it.
If you view terrorist organizations as rational actors, constantly working to cultivate a delicate balance that keeps popular indigenous support, nations from unifying and the underdog illusion alive, then it certainly becomes possible that part of the reason we haven't seen a terrorist attack on US soil for 7 years is because they simply have chosen not to.