You raise an interesting question. I mean the obvious aside that they would get their asses kicked if they tried, but from their perspective why wouldn't they? Interesting thought.
I fully believe that the GB or at least most of it's members are kool-aid drinkers themselves. They buy the shpeel they put forth. But one big thing I think is that this generation of the GB are no longer biblical scholars of any sort, they are watchtower scholars. They have no idea what the bible says in any scholarly way, they only know what the watchtower has been saying the bible says. Part of the WT line for the past several decades has been to not engage in debate, avoid it at all costs. Do not argue with somebody, if they want to argue forget it, move on. And I think at this point they don't care about the theological accuracy of what they believe, because they are kool-aid drinkers themselves and not biblical scholars. Just like the cult members they control, they don't believe it because it makes sense, they believe it because they think they are chosen. Whether or not what they believe is accurate or true is of secondary importance, so why bother arguing with people that are going to try and argue that what you're teaching isn't true? I think they've given themselves permission to ignore the world and focus only on keeping the flock obedient to them, which in their mind is what is actually important. Was it Fred Franz that said in court that it didn't matter if their prophecies were true, or their teachings were true, it only mattered that everybody followed him in lock step like a marching army? That's the governing body view now I think. It doesn't matter if they are right, it only matters that they are obeyed because they are chosen, and publicly debating wouldn't accomplish that goal. It's some pretty stout kool-aid.