What is the power and extent of the effect of positive thinking on your reality?
If you are trying to achieve something that is not empirically verifiable, then that belief can be very effective in achieving the goal.
It is either believe that you have achieved that unverifiable goal, or admit that you were a damn fool. And nobody want's to admit to being a damn fool.
Religion's claims are mostly about achievements that cannot be empirically verified.
Jesus was a liberal hippie