I was an elder when 1975 came and went and NOTHING HAPPENED.
It was actually discussed among the elders secretly from the congregation.
I would say that most elders ignored the fact that nothing happened - and many actually said that it was a "test from Jehovah" to see how many JWs would fall away. I heard one pathetically comment that maybe the real end would come in, say, 1977 just to see who remained faithful.
Seriously - they were actually saying that Jehovah - through the one true channel of the Watchtower and Freddy Franz - was TESTING HIS PEOPLE THROUGH A FALSE PROPHECY!!!
I think at least 90% of the witnesses (and at least 98% of their elders) are too brainwashed to realize anything - let alone that they are being duped.