If i can be the Devil's advocate for a minute, the reality is that the current GB members have been dealt a pretty dismal set of cards, from previous leaderships and now they must do what they can with it.
It's a pretty tough legacy they received, with all the predictions and doctrinal concoctions, passed down from all the "bright" minds of folks like Rutherford and F. Franz. So now, they have to dance with who they brought to the ball.
It's a fine line between trying to be reasonable and not letting the house of cards crumble.
Also when the society moved towards an arrangement of a Governing Body they pretty much sealed the maintenance of hardcore beliefs of JWs.
Whereas before there was a chance that the one man in charge had a change of heart, or a moment of clarity, with the current arrangement, even if one or two members have a desire to "clean house", the rest of the group logically will turn on them and force them out to maintain the status quo.