You are frustrated because you are thinking that FACTS matter to your wife.
Her belief system isn't driven by facts.... it's driven by the emotion that is produced when she hears somewhat plausible explanations of life's big picture issues . Although none of them are provable, they allow her to have a warm fuzzy feeling about her future and to wrap up all the unknowns in life into a nice little package, provided by the JW's and outlined in the products(literature) they sell.
A person has to be emotionally ready to face the hard facts of life and many use religion to shield them from having to face them...ever. Help her become strong as a person so that she doesn't need to hide behind a magical belief system to feel safe.