For quite a period there was just silence; almost like they hoped if nothing more was said about 1975, then just maybe people would quietly forget the matter. In fact, according to Raymond Franz in Crisis of Conscience, that is what at least one Governing Body member strongly suggested doing.
Also in that same work, Raymond Franz readily admitted that when an apology was finally made (in 1980 - i.e. five years afterwards), it was a very watered down one!
Other than that, over the years the WTS/GB has continued to deny the obvious about what they said and wrote in the years leading up to 1975. (One example of many comes to mind at a Circuit Assembly late in 1974. The District Overseer delivered a talk, in which we were cautioned about being "too" dogmatic about this date. However, he then completely undid what he had just said, by the concluding sentence of his talk, in which he loudly stated "But We Still Stand By Our Date of 1975!!!!!" )
Needless to say, that remark brought a burst of applause from the audience. Bloody fools the lot of us!