Nobody ever said that the end was coming in 1975.
Nobody ever said it quite like that...... The assertion that the end would come in 1975 was invariably expressed as the greater meaning of multiple statements
JW's for example will deny that it was ever stated that they alone will survive Armageddon. They will say, "Show me where we said that only JW's will live!" Well, there are many more complex ways to make a statement besides a simple and direct assertion thereof. Consider the following two statements:
A. Only those that speak the pure language will survive Armageddon.
B. Only Jehovah's Witnesses speak the pure language
Unless one has some serious reading comprehension problems, the assertion that only JW's will survive is clear and undeniable when these two statments are taken together.
With 1975 it was similar because two or more simpler statements, when taken together would add up to a greater meaning. For example (And I'm paraphrasing here because I'm away from my library, but I can get you references if you want.) it was stated:
A. In order for Jesus to be Lord of the Sabbath his millennial reign would have to be the seventh in a series of 1000 year periods
B. 1975 will mark the end of 6000 years since Adam was created
C. Eve was created in the same year as Adam and it was at that point when God's Sabbath Day began.
Since Jesus himself is the one that declared that he was "Lord of the Sabbath" this series of statements, which were all contemporary with each other, directly align the honesty and integrity of Jesus himself with the notion that the end would come and his millennial reign would begin in 1975.
I had a JW upbringing (Even though I'm not a JW) and like Big Tex, I was there too. This method of indirectly making a statement was not lost on the JW audience especially given the fact that comments made from the platform at assemblies were much more frank and to the point. A few speakers even flatly asserted that the "Door" would be "Closed" before 1975.