If the Stasi was so well organised, why did Communism collapse?
In the Communist ideology, there's no place for criticism. Instead, the leadership structures believed that socialism is a perfect system, and the Stasi had to conform them, of course. The consequence was that despite all the information, the regime couldn't analyze their real problems, and therefore it couldn't solve them. In the end, the Stasi died because of the structures it was charged with protecting.
Hubertus Knabe on the fall of East German Communism.
I'm not sure how accurate his description is, but it's an interesting idea. A system that assumes it's perfect has no way of questioning itself, no way of turning back or correcting their course. If this is true, then the only possible outcome for a perfect system is collapse.