There hasn't been a lot of academic writing about Witnesses outside of the medical field, where their refusal to accept blood transfusions has generated a lot of work. The one recent text I can find is George D. Chryssides, Jehovah's Witnesses: Continuity and Change.

Chryssides devoted the tenth chapter of his book to the Witnesses' complex relationship with prophecy. The first line that insulates the religion's Governing Body from overwhelming criticism (besides the fact that the religion punishes dissent quickly and ruthlessly) is that the Governing Body does not claim to make prophesy themselves. Rather, they claim to only be the interpreters of biblical truth, highlighting or revealing prophesies that have been there all along. As such, flaws are in the interpretation of the prophesy, not in the underlying prophesy or in the person of anyone who claimed to be a prophet themselves.

Secondly, the Organization has generally not predicted a specific end of the world. Instead, the Witness cosmology is built around the idea that we are living in the "Last Days," a period of decline where any disturbance or tragedy can be construed as a sign of the current system of things' imminent collapse. For example, while the world did not end in 1914, Witnesses continue to point to that as the year when Satan was hurled from heaven to Earth, and point to the outbreak of the First World War as proof that an evil presence was making itself known. This awarding of partial credit lets the Governing Body salvage their reputation when a predicted doomsday seems to fall flat.

The best-known of these failed interpretations occurred in 1975. This quote from the August 15, 1968 edition of The Watchtower shows how couched the language the Governing Body used was:

Are we to assume from this study that the battle of armageddon will be all over by the autumn of 1975, and the long-looked-for thousand-year reign of Christ will begin by then? Possibly, but we wait to see how closely the seventh thousand-year period of man’s existence coincides with the sabbathlike thousand-year reign of Christ … our chronology, however, which is reasonably accurate (but admittedly not infallible), at the best only points to the autumn of 1975 as the end of 6,000 years of man’s existence on earth. it does not necessarily mean that 1975 marks the end of the first 6,000 years of Jehovah’s seventh creative ‘day’.

There was a marked decline in Witness membership after 1975, but not enough that those leaving attempted a formal schism or that the church ceased functioning. Internally, the religion moved on to another prophesy: that the generation alive to witness 1914 would not pass away in its entirety before the beginning of Armageddon. Now that only a small number of people born in 1914 are still alive, the official publications of the organization have begun suggesting alternative readings of the word "generation". Finding such new interpretations of scripture is one of the key responsibilities of the governing body.

Sadly, I wasn't able to find a systematic study of what people thought of Witnesses after the failed '75 prophesy.