Me and an elder? The elder would win. Because 1 people believe what they want to believe. That's why it is so hard for any one to figure out what the truth is and what is really going on. You have to get to a place of overcomming your personal bias and prejudice.
If I convince the elder he and the troof is wrong. He looses everlasting life. That's not good. That is a powerful shader of reality.
In my world people dont leave the troof based on one persons comments. It is the end result of time and experiences and periods of being aware and cognizant of ones surroundings. That's not going to happen over the short haul.
Also, I personally dont carry around a large list of why the watchtower is wrong. In my world if I find one thing wrong and it claims to be from a perfect God, it is all wrong. That one thing is I Iived thru 1975. I didnt get an education, I have gotten old, and life is a difficult struggle because of them aholes. A 30 year old elder isnt going to buy that. And if hes a 60 year old elder, theirs no fool like an old fool.