I'm too freakin' lazy to do all the documentation on this, so I'll just throw it out here and see if this clicks with others...
After the stupidity of 1975, growth sputtered and stopped. "Growth" was negative two years of the late 70s, as I recall. What to do?
For one thing, they started harping on "this generation", "the cry of peace and security", "the king of the north", etc. in new, more colorful litteratrash from "mother".
For another thing, there was a witchhunt. After clearing "apostasy" out of Bethel, they now were enjoying "jehovah's blessing".
Another major thing that stopped the dubs heading for the exit, was the hard line on treatment of the disfellowshipped that started in 1980 or 81. I don't remember it all that well, but I had older ones explain that things really "tightened up" after a couple of study articles. And since then, the hardline is being held.
If the historical example of the late 70s is legit, one could assume that many would be heading for the exits if the ropes were loosened.