The Watchtower's only power over Jehovah's Witnesses is fear. If WT became less tyrannical and legalistic, and admitted they don't have all the answers and have been horribly wrong about many things, I believe most JWs would reconsider their affiliation with the Org. Other than a lifetime of hard work, what does a JW get back from the religion? Nothing. If the spiritual carrot is exposed as hopelessly flawed, then the captivating force is shattered.
WT keeps people in the Org. by using emotional blackmail- disfellowshipping.
WT maintains the illusion or correctness by holding to the exclusivity of being the only right religion.
Admitting mistakes means undermining the claim of being guided by God and opens the door to critical-thinking and questioning among the rank-and-file. The governing body must retain absolute control in order to survive.
The GB would rather have a religion that appears superficially cohesive, glued together only by fear, than be honest and humble and risk losing members.