I actually think that in a lot of ways it's in their best interests to push a new hard date like 1975. They'll get one last good push out of any fence-sitters, and they'll likely rake in a lot of money from the die-hards. They might even get enough short-term growth out of it to sell the idea that they really do need more KHs built in the US. Then once it comes and goes the fence-sitters will leave allowing them liquidate a lot of the real-estate assets and get down to a slightly smaller, but fiercely loyal following that will generate higher profit margins. They'll have lower overhead but I suspect those that they lose are probably already not donating very much so they could actually come away with more profit in absolute terms as well.
Those that they're left with after the disappointment will likely be even more loyal to the cult than they are today - this is seen time and again in doomsday cults, when the prophecy fails those that stay double down on their dedication to the cult and often are invigorated into proselytizing. Having shed those that already had their issues with the cult and further securing the loyalty of those that remain, they'll find it easier to make the sweeping organizational changes that they need to make in order to maintain viability with less "murmuring" going on at the grassroots level.
The GB is getting old (again) and they no doubt want desperately for the end to come soon. The cult is "under attack" from the authorities for their child abuse and shunning policies too, so they probably believe the end is near if they're true believers. This time around I do think they'll be more careful and keep the date prediction to CO talks, convention talks, and maybe online-only content, so when it doesn't happen they won't have to work so hard to hide their failed prediction. If they do put anything in print, you can be sure they'll edit it after the fact in their online library.