The IRS building is wired by special ops to collapse at free fall speed.
Stop trying to justify who, why, or how they got away with it. You have no way of know whether or not it was Special Ops. You say the probability of the conspiracy being more complicated than what the official story tells you is low, but probability of the physics defying collapses was lower than that, because you don't understand the physics.
You are basing your assertions on a complete void of knowledge of physics or any sort of military operations whatsoever.
Realistically, the probability that the conspiracy was more complicated than what you were told is pretty high, unless you believe it's OK to defy the Laws of Physics that have been widely accepted for hundreds of years. THEN, it's low.
Contrary to what I want to believe, the probability that the story is incomplete is higher than the probability that the story is complete. You guys proudly claim, while beating your chest, that no one will ever know what really happened. Yet you then mysteriously rule out any other possibility. Now, to back up your leap of faith, you are debunking the official story.