I had a chance to speak to my nephew (born in) a few weeks ago, and he had absolutely no idea what anything means ( no idea how you arrive to 1914, no idea that Jesus is the mediator for FDS, no idea what the current generation understanding is, no idea that you can take blood fraction, etc etc etc).
Yet, he goes out preaching.... The issue is that preaching these days amounts to something like " Hi, isn't the world bad? Please take this magazine and if it's ok i can come back next week to give you another one" .
This says it all. Most witnesses including my wife have no idea on any of this stuff. They just "know" it has to be "the truth".....and if you challenge that pipe dream you'll draw that person's righteous indignation. They can't explain the bible. They can only talk about certain points of major doctrine in which they've been handed cherry picked scriptures taken out of context to apply. They've been told that "faith without works is dead" therefore in order to earn their ticket to the new system they must perform the works they are told to perform. There is no thinking. It is total and complete trust in the leaders of the organization.