Apognophos - I think you are largely right on the money. I think another element to it is in how much you have invested in the organization when you learn particular bits of TTATT. If you're extremely reliant or invested in the org then you're more likely to try to rationalize away anything you learn. That's one reason why the org wants everyone to pioneer or go to bethel or be an elder. The more time you invest into the org, the more traumatic it would be if you learned it was all a sham, so you're more likely to rationalize away anything you do learn.
That's also why they have secret elder's books, and secret elder's training and they keep the goings-on at bethel secret. By the time you get to the level where you are allowed to know the secrets, you've already invested so much in the org that you'll find a way to rationalize it. If someone is studying and was handed a fully annotated elder's manual to read, they'd almost certainly leave the organization, but if you take that same study, wait a few years, get them to pioneer for a while, then hand them the elder's manual and have them annotate it themselves, they're almost sure to stay on board.