So really just how long is a generation in regards to the length of human life ?
In regards to WT theology, does it really matter? The WTS said that the generation that was alive in 1914 would not pass away. Any way you cut it, the generation that was alive in 1914 is, for all practical purposes, gone. Dead. Passed away. There are some straggglers, but the generation is gone.
The WTS can try to define the word generation any way they want to, but their own words from the previous 50 years come back to haunt them. Not only their words but their pictures too:

This whole generation thing is just amazing to me. It's more damning than any other prophecy or teaching. As bad as 1975 was, they were always able to weasel out of it because they never came out, in print, and declared the end of the world by 1975. But this one they did. Multiple times, over decades. You can pull out any number of publications and find the teaching still there. So for them to come out and try to pass off this overlapping shit takes major balls or stupidity. I can't quite figure out which...maybe stupid balls, I dunno.
As plain and simple as this is, I'd like to think that many JWs will sit up and take notice, like many did after 75, except more. But will they? Are they too indoctrinated? Too lazy? Too scared? Maybe that's the amazing part. It's so obvious to an outsider how full of shit this religion is, except those on the inside can't see it.