If you are/were an active JW, you are now here on JWN so, for whatever your reasons, you woke up to some degree- hopefully a great degree. So what I am saying may not apply to you.
I know that if I had not already left, I would have stormed out on the day they studied "overlapping generation." I am quite confident I couldn't have stayed for such an obvious switcharoo just to make the end seem imminent and try to explain how WTS was wrong, but not entirely wrong in the past.
But I had to wonder how that change (or others) didn't cause most JW's to walk out. My best theory is that they are too invested in WTS and just have to hang on and believe. They want to believe, no matter how ridiculous the doctrine gets.
Here's a great magic example from Penn and Teller that shows how really simple it is to trick people:
https://www.youtube.com/watch?v=2H81A3bU68k
Part of the success of magic is that the audience wants to believe, despite their deep-down knowledge that it's just an entertainment trick. The point of the revealing is that, no matter what nonsense the Watchtower prints, many members simply don't question it.
Here's an even simpler trick where a fast eye could catch the moving of the rabbit:
https://www.youtube.com/watch?v=wSOQfAEVRbc&NR=1
I loved the television show, "Magic's Biggest Secrets Finally Revealed" that was on a few years ago.
I think it's because the show reveals that complicated tricks really are not so complicated. It's similar to the WTS tricks with the Bible and twisting of logic. It seems complicated until you know the trick. JWN and other sites reveal the trick, but only if you want to know.