I see all the outrage about the "generation" change, but these changes have been going on all the time. The gullible swallowed it before, so the GB probably reckoned they will lose only the weak ones anyway.
I have not read their excuse for the current position, so I can only go by the few comments I have read. From those comments, I think the GB have either mismanaged the change or this is yet one more step in a long saga.
If I were the GB, my argument would have gone like this:
(1) Jehovah God anointed Rutherford and his crew in 1919.
(2) When Rutherford died, the mantle passed on to his successors, just like the Apostolic Succession claimed by the Popes of the RC Church.
(3) Therefore the "generation" refers to this continuing passing on of the baton to the successive members of the GB.
(4) In turn, since the Governing Body represents the earthly FDS, this means that the members of the FDS (the Anointed who are on earth), share in the GB's "Apostolic Succession".
Maybe I should copyright my reasoning so they can't use it next time they need to make the change.