The overly specific predictions make these "prophets" look foolish in our eyes, sure, but they already looked foolish in our eyes and even if they got one correct by chance we'd still be unimpressed. If they fail prediction after prediction and maintain, or even grow their following, can it really be said that specific predictions aren't working out for these guys? The Watchtower Society hasn't exactly lost its influence after all its failed predictions. I'm sure it lost its grip on a few adherents every time a date came and went, but that may well be worth it to them as a necessary paying of the piper, for all the influence those predictions bought them on borrowed time while they looked viable. Even Mr. Camping: yeah he publicly made a buffoon of himself, but did he have to give back all the money he made between proclaiming his prediction, and the jig being up? I think the prophets aren't stopping because between making the prediction and its failure, they rise to a level of power and influence over the minds of their disciples that can't be had any other way. And they'd rather have it temporarily to exploit as they can, than not at all.