As a whole the GB are captives of a concept. The problem is groupthink is woven into the fabric of the organization. And I suspect, at this point the Organization has a life of its own that is bigger than any one person or group within it.
What would happen if by some miracle the GB all simultaneously realized that it’s all BS? Would they be able to get the writing department to publish a special Watchtower magazine in which they come clean to their readers? Or would the brothers in the Writing department call the Service department and convene a special judicial committee to “clean” the organization of the “apostate GB” and appoint a whole new group of GB who are loyal to the core values and doctrines of the Organization?
Think about your local Kingdom Hall. Do the elders know it’s BS? Maybe one has serious doubts. Let’s say he allows himself the luxury of exploring his doubts. He learns TTATT. He’ll either keep his mouth shut because he can’t get out because of family, or he’ll start talking about his doubts and either get DF’d or beat down by the other members of the body until he fades. Meanwhile, the other elders on the body are reminded to squash their doubts or they might end up like elder Apostate who lost his family and his position. The same dynamic is at play in Bethel.
The Organization is set up to protect itself against dissenters and independent thinker and those who know it’s BS.
Of course, some people know it’s all BS and are in it solely for personal gain. (Just like in your local Kingdom Hall.) But those people are isolated, either aware of the dangers of speaking up, or they realize they have a good thing going (position, prestige, family, tradition) so why rock the boat.