You are so right Adam, in the few candid and long conversations I have been able to have with JW's it has always become evident at the end that their decision to stay is entirely emotional. Hence any change in doctrine or policy does not faze them, they adjust their thinking to accommodate the new teaching.
And yet, all of us who left had that emotional attachment too, but we left, and for a reason or reasons, just occasionally some leave initially for emotional reasons, they have been hurt by someone, they soon have plenty more solid reason never to go back, even if the hurt is removed.
I think it is a good question to ask all JW's, "What would it take to make you leave?", not that you will get an honest answer, but the question may stay with them, and make them examine how much crap they have put up with so far.