Part of the WT indoctrination is a self-destruct mechanism--leaving the cult will cause us to become an alcoholic, immoral, our family will fall apart, and everything will go so wrong that we may die or wish that we'd die.
As mentioned by others, there are plenty of active JWs that are a mess. With the fear, obligation, and guilt that's heaped on JWs, they can't reason how WT is the real source of unhappiness in their lives.