" The borg must really love those sprawling JW dynasties.". I am sure the Borg. does love them, as they give a vague, but actually baseless, kind of credibility to the "religion".
Thinking about those dynasties that I know of personally, few of them now have younger ones, under 60 say, that fully believe, they may still attend meetings, even go out in F.S, but they are PIMO, I know that because several of these people have told me so !
The dynasties do not have many years before they are no longer made up of J.W's.
The Org. is withering away, the G.B do not care, it will "see them out", they will live their life of Luxury and ease, it will be the ones who come along in the next few years to fill the gaps as today's G.B dies off, who will oversee the final expiration of the Org.