979
Also Peter Thiel.
EOTWAWKI has always been a mythical fantasy, including the futuristic interpretation of Revelation regarding the second advent.
This is really the only way that cults in their late and isolated stages can hold together, not only that the end is neigh, but that it is imminent, a few month's away at longest.
And that is because the devout are expected to be squeezed. They're expected to toil to breaking for sake of the community and their leader.
In the cases of communes like Jonestown and the Branch Davidian compound, there's always a dire labor shortage. There's consistently more work to do than can be done by the labor force available to make sure everyone is fed, housed, treated for illness, clothed and so on.
Exploited labor cannot work under pressed conditions for super long, but giving them a hard deadline weeks or days away, helps a bunch. Doubly so if it comes with a guarantee of eternal bliss (or a UFO ride to join the space aliens).
Naturally, at least for all cases so far, the deadline comes and goes. This is usually when the prophets recompute and provide another deadline. Again it can only be a little bit longer. Even a year later and it's too much to ask.
With each passing doomsday that doesn't manifest, the cultists get more antsy like the crew of the Abraham Lincoln. Suicide and apostasy rates rise, then soar. Discontent heats up in the community, as each false apocalypse deteriorates confidence in the next one.
Eventually, something has to crack. In the 20th century US, reports leak to the authorities about the poor conditions and the abuse (there always is, in a large enough population), and in the face of intervention, the cult leader goes scorched earth like the Nero Decree.
In the meantime, the list of failed apocalypse predictions grows ever longer without any yet coming to fruition.