" There must of been a money making scheme behind the 75 thing for WT. Or something up to no good."
I don't think it was a calculated thing, by " The Society", I think they were borne along on the waves of enthusiasm of Mad Freddy Franz, who backed the date, and dropped broad hints in a talk that HE was convinced it would be " the End of the System of Things" by October 1975, though he laughed, and said " But we are not SAYING...." Imagine how that ramped up expectation ! The Oracle had spoken ! But much like the Oracle of Delphi, you could not trust the words, they could mean more than one thing.
It had the effect of reactivating many in the late 60's and early 70's, and it brought in converts, a good number from both groups drifted off when expectation was unfulfilled.
False Prophets by any measure !