If when we die, we have paid for our sins and are all going to heaven, what difference does it make? God gives us all free will -
And, I don't know that JWs are any more "worn out" than any other group of uneducated, low wage job earners. Things are tough out there. There are plenty of happy people in the organization, but there are plenty of people who are not. Many people drawn to religion, especially fundamentalist religion have a fundamentalist mindset to begin with, and are looking for "something", and are probably at the very least dissatisfied on some level if not out right unhappy.
True happiness is not circumstantial.
My 2 cents,
DS