I wonder why they didn't promote go bags in 1975? Weren't those Witnesses just as important as those today? What changed?
I became a JW (at age 22) in 1973. With oil shortages, wars etc lots of people were preparing for trouble. We all knew Mormons were supposed to have 7 years of food. But we all congratulated ourselves for being so much more faithful. We didn't need to get ready because when the time came, Jehovah would protect us.
From my standpoint, I'd say what changed is they lost faith - in the GB, the elders, the magazines, each other, and themselves.