once again, out of my own expereince, and of few I know, there are sincere types of elders, who may have some doubts, but "wait on jehovah".
Sooner or later this may create a problem (like in my case), but in the meantime, they really think, they work for the benefit of the flock and under the direction of God.
Especially as an elder, you are kept busy with indoctrination of others and yourself, there is little time to pursue doubting thoughts that come up in your mind.