This is true most JWS of even my era in the 60's and 70's didn't know that the WTS under C T Russell proclaimed that the generation starting from 1874 was the generation to witness the GT and 1914 was the assumable year for Armageddon.
IDK I feel like this is different somehow. In those instances there were recalculations or they would change tactics and start looking at other prophecies, jubilee years, 7000 years since Adam etc. In this case they have literally nothing to base this on at all except trying to redefine a common term. I don't think the young people are fooled one bit and middle aged people live through the failure. Then again I always thought "Millions Now Living Will Never Die" was about the generation teaching too until I finally read it for myself.