I agree with Smiddy that the GB are embarrassed by the earlier publications (who wouldn't be?). I kept a couple of ones from my mother's library (with quotes relating to 1975 and the "end of the system by the end of the 20th century").
I also obtained an original 1980 yearbook off of Amazon for a few dollars.
The last thing they want to see is someone with physical proof of all the crazy stuff they wrote earlier.
It also occurred to me that we are in a new era - the WT and AW (are there still Awakes?) will be quite rare in print and hardly seen by people who are not JWs. Printing is fading away. This would have been absolutely unthinkable in the 70s and 80s.
It does make it easier on the GB, they can just re-write history as needed. Modern society, because of the internet, doesn't maintain a "tribal knowledge" of literature based on books, as in centuries past.