I tend to agree that it is unlikely for a GB member to leave even if he wakes up and becomes PIMO. The disadvantages for a GB member to actually leave the org and become an outcast and vilified, would outweigh the social benefits i.e. remaining a pampered demigod albeit mentally out.
The big wigs in any operation or scheme or organisation religious or secular, if their heart isn't in it, become just actors who capably play their roles and perform as they are expected and are rewarded accordingly. This too can happen at JW HQ. Many Bethelites know things are seriously wrong in the JW world.
This situation demonstrates that the only GB member with the courage and honesty to act in accord with his conscience was Ray Franz. What a shining beacon of integrity that man really was!
The GB just like the organisation they control, is becoming hollow, just yielding the outward appearances of what they pretend they are doing, preaching salvation to the world. The world population is now growing faster than they are and the message is increasingly less interesting, less credible, less desirable, less valuable.
In time the appearance of conviction and "God's blessing" will diminish in the JW org but power hungry JWs will always want to be lording it over the humble sheep so GB members will probably hold on to the bitter end railing against Satan's world and getting the plaudits from the remaining faithful.
The flock have to live with cognitive dissonance, it keeps them dependant--then why not the leaders? Possibly because narcissists don't actually care about other people.