I have to agree with the idea that 1914 has a shelf life, but I suspect for a while yet.
To some of the above who believe it can't be dropped, the difference with JW's and other faiths who have changed their beliefs is that a) they have focused on 1914 for so long (almost 140 years) and b) it is at the heart of the public ministry. In 2064, how ridiculous will it look to talk about Christ's return 150 years ago? And still nothing has happened.
So how could they drop it?
There are two obvious ways. Overtly or covertly . Overtly could be done if someone can devise an 'inspiring' way of doing a whole re-work of their numbers game. If it could include 1914 and then have a new start date, and a return of the old 'within a literal generation' then job done. As long as the R&F can believe that the end is imminent they will continue to put their lives on hold.
Covertly means quietly dropping ala the Kings of the North and South. Mentioning it less and less and the decades go by. Until it becomes meaningless to the young JW's of the future and it's never mentioned again.
As they don't seem to have a new seer like Freddie Franz then covertly seems the more likely option in my opinion.