1975 was nothing more than a marketing strategy devised by the WTS leaders.
They intentionally pumped up the fear that judgement day was coming soon to attract attention to the literature they published and stimulate the proliferation of those publications to the public.
Of course they were not going to apologize after nothing happened , to do so would potentially expose the truth to their intentions.
The WTS leaders like to cut things from all angles when they do things obliviously wrong or deviously corrupt, they just say well we are imperfect men too.
There are other fear mongering charlatans around particularly in the United States where there is unregulated religious freedom in that country.
To note , all the money cultivated by these charlatans never has to be legally returned to those who gave them money. $$$