I think there are 2 main types of JW's who voluntarily become 'Awake!' and "see through the Watchtower."
1. Spiritually minded people who cared (and maybe still do) about the differences between what the Bible really says and the WTB&TS's interpretation. In this group I would include people who have gone on to other belief systems.
2. Socially & somewhat spiritually minded/interested folks (like me) who were more or less raised around the Truth ™ and believed it was the good people and the Love ™ they had that id'd them as "God's Chosen ones."
I think both of the above groups have to have something BIG happen in their JW lives to make them wake from their trance of JWism.
It had to get very personal.
For me, my "lack of faith" made me "spiritually dangerous" and began the slow destruction of my marriage. When my Mom died over the blood issue -- I was finally, fully Awake! But, I was the only JW out of a hundred in my family that did leave so far.
This is a great question, Wanderer. If we can figure out the answers, we can help a lot of other JW's 'out'.
Rabbit