Some Witnesses? I don't recall a single believing Witness who did not believe it. My family was a bit skeptical b/c of past Armageddon dates. Altho my mom ordered me not to worry and told me of what happened when she was my age, I was terrified. 1975 was a very bad year for me. I believe it was a self-fulfilling prophecy. I had already left the Witnesses and studied academic NT in college. My rational mind mocked them. I felt sorry for the people I cared about who believed it so fervently.
I recall the anticipation. In fact, I recall Franz announcing it at Yankee Stadium. Maybe his remarks were more measured than I recall (and everyone else recalls) but my point is that Bethel knew for a fact that Witnesses were relying on that date. No steps were taken to diminish the ardor for 1975. I recall no explanatory article in the Wt that Franz said x and we believed y. People relied to their detriment. No harm in that - members of many religions rely to their detriment on teachings that change. To blame it on the lay people is a travesty. Franz just had to look in the mirror for someone to blame. I never knew the biggies on a personal level. They were all long time believers who were older than my mom. Knorr and Franz had to face disappointment with other dates.
Why was this date better than all the past dates? 1975 was a catastrophe for the Witnesses. I wish I knew whether they truly believed. If Franz was just speculating, revealing a pet theory that was not a directive of Jehovah, he should have kept his mouth shut. Perhaps if you knew him from a study at Bethel and had ongoing contact with him, you could figure out he was not divine. I want to let younger people know that I was a witness to his Witness.
One curious part is that Yankee Stadium is packed and Franz warned not to tell worldly people. It wasn't the right time. I was a teenager and had no faith but it scared me b/c I knew I would never survive Armageddon. Something tells me that the New York Post and Daily News dispatched reporters to cover the local event. Maybe the religious editor at the New York Times sent someone for local religious events. His speech was markedly different from your regular convention Armageddon is coming t'mw' speech.