Unfortunately, people make a choice to stay in religions for more reasons that the rationality of the theology (or irrationality, as the case may be).
For many, it's more about the social, familial, and emotional needs that are provided by being a member (or, like designs said, it's more about avoiding taking a hit in the pocketbook, with the religion serving as an unofficial Rotary Club: the old saying is "the hardest fact to get someone to accept is that which threatens their and their family's livelihood").
The JWs and Mormons fully-understand this dynamic, and have maximized the non-rational factors as much as they can, making the cost of leaving so high that even if someone KNOWS the Truth isn't actually "the Truth" (i.e. being a model of reality that is confirmed by observations) they won't decide to act. Ironically, Simon Peter even voiced his doubts to Jesus, saying he saw no other alternatives for his life: "But Lord, where else would we (the apostles) go?" Those words could've been voiced by a JW or Mormon who says, "but I'm a born-in, and my entire family are JWs: where else would we go?"
(that's actually a fallacious argument based on 'appealing to personal ignorance of available alternatives', and thus the choice is a false dichotomy, eg who says anyone NEEDS to believe in ANY religion?)
If people aren't willing to stand up for reality, AKA truths, then they deserve whatever ethical and moral torment they experience in their lives. They're wasting their lives built on living on a lie or based on a pipe-dream, being the ultimate examples of hypocrits who are trying to get others trapped into a lifestyle that they themselves KNOW is a lie. At some point, individual responsibility has to enter the picture, and a person has to decide not to waste THEIR life; it's only themselves (and their families) that they're hurting, in the end.
I guess JWs (and Mormons) are living proof of the old saying, 'misery loves company': apparently misery is even willing to spend its Saturday mornings going from door-to-door, looking for new recruits to join the misery club.