Great answers here. Now, my take- Watchtower has too many older members who clearly remember that they were heavily promised that the "generation" would not all entirely die until the end arrived.
Watchtower is a Doomsday Cult. Doomsday Cults need a time reference in order to recruit/retain. Watchtower has nearly given up on recruitment and focuses on retaining members. They tried abandoning the attachment of their "generation" to 1914 with their 1995 doctrine that the generation was "wicked people of the time of the end" without any real dates/chronology attached. It hurt retainment, so they went back to date-setting attached to 1914.
Eventually, the calendar will force them to abandon this entirely, but not just yet. All the current Governing Body members will be dead by the time that happens, so they just won't sweat or lose sleep over the problem down the road.
