I have to agree with SBF on this. In a nutshell:
SBF: JWs will often only be convinced JWs are wrong when such a conclusion aligns with their own interests.
People make decisions far more on emotional and other non-intellectual bases than they realize. They then create an intellectual justification, afterwards. I understand that this has been proven by experimentation many times. Eg, google "Festinger and Carlsmith experiment". It tends to happen at a subconscious level, so after a while people don't realize it, and just remember the intellectual justification.
If you look at advertising and marketing, it is overwhelmingly about hooking you in emotionally, rather than intellectually. The advertising industry wouldn't do that, if it didn't work. Another example: I was told once that the Catholic Church had a major problem with priests leaving the priesthood once their respective mothers die.
I suspect that for every individual that leaves the cult for entirely intellectual reasons, at least another 50 leave partly or wholly for other reasons (too inconvenient, too boring, too unpleasant, etc). They then quickly find the intellectual justification to stay away, and there is plenty of intellectual justification available to choose from.
Unfortunately what that also means is that it is a lot harder to wake up a cult member than some people seem to think.