In western countries door to door work is already completely ineffective. the public doesn't give a flying you know what about the org. Nobody in my territory even comes to the door. The level of growth is almost soley due to relatives and children of JWs in the west. We had 2 baptized at the last circuit assembly. baptims numbers in the west are decreasing. to the general public JWs are irrelevant.
Internal apathy is what will kill the religion. Continuing to cry wolf with yearly historic campaigns will eventually wear people out. Not wear them out in the sense of making them tired, but causs them no longer take anything the GB says seriously. Already most young people are just going through the motions. They remain in because they love the instant friends and the social aspect. That's the part I will miss most. Some people achieve levels of popularity in the organization that they would never achieve in the world. JWs are a very demanding religion, but its becoming less demanding. This lessening of the load ironically will cause greater apathy.