The next generational big date to watch is 2034.
By then the JW Organization might be 12 million and the over-lapping generation idea, although much loved, isn't going to hold water.
Sometime within the two decades remaining until 2034 that's when there'll be a change in the generation description. There could be an expansion to yet another overlap.
If the change in 1995 can be a guide then they'll lose some members. But all this would do is thin down the ranks a little by removing those who are the more critically minded JW's. The thinning down will result in ultra-loyal Governing Body followers who will be ripe for a push as 2034 nears.
So as the time is short for the 2034 date there may be another 1975 rerun. The new rallying cry will motivate publishers to do more for 2034.
Of course this date will arrive, many of us will be history by then, and then there'll be another thinning as there was among those who stayed alive until 1975. Except--and this may be crucial--in 1975 there wasn't an internet available.
The internet is already squeezing the Watchtower's monetary gonads by turning away new members before they take the plunge. This could make them fizz out into a shadow of what they used to be but fanatically fundamentalist, or make them more relaxed, more tech savvy and shed off the big cultish beliefs, like no-blood and DF'ing.
Whatever the case, I agree with DD that they'll be forced to amend the overlapping-Gen idea that they so much love right now. It could very well be seen as the anointed's-Gen that DD points out because there isn't a big jump from having one overlap, then two, three and eventually a continual overlap.