One issue? NO, it was the accumulation of the problems.
" By their fruits, you shall know them..."
A 3rd generation JW, I was at Bethel in 1975. It wasn't just the accumulation of failed prophecies; it was the lack of Christian qualities and bald-faced lies at HEADQUARTERS. The two faced abuse of the rank and file, telling them, "The end is any day now," while buying and selling real estate and making long-term plans. Letting them believe they had "angelic protection" in "the Lord's work" and actively hiding the dangers sisters were exposed to in field service (rapes and kidnappings). The study and keeping of Witchcraft books in the Bethel Library. Rampant fornication and Homosexuality AT BETHEL. And the hiding of unqualified (some serial fornicators) men being appointed to positions of power as Elders and Governing Body positions. Zero evidence of Holy Spirit.
At first I chalked it up to "imperfect men", but after the 2000s it was obvious NOT ONE WATCHTOWER PROPHECY HAD EVER COME TRUE. It became obvious CHILD MOLESTERS were actively hid. And the flock was regularly lied to at every convention about the accounts report.
As an Elder, getting "HEAT" from Having to take a stand against hiding a notorious child molester from being appointed (and having to go to the police), having to write letters to the service desk and GB members I knew PERSONALLY about OBVIOUS SLAM DUNK CRIMES, like Domestic violence, child molesting, convention faked accounts, and financial abuse of seniors, was the last straw. Like my little overloaded Donkey photo...it became obvious there was nothing "Godly about the Watchtower and the Governing Body" and their LIES ie: "Theocratic Strategies". Satan is the "father of the lie"...there is nothing Christian about "Theocratic Strategy".
The fruits were rotten, even illiterate felons in prison know Child molesters are trash. It wasn't 607, 1975, or some obscure theological difference, it was simple basic moral ROT, from the top... down....and I no longer could stomach being any part of it.