My current Taki's column doesn't attempt to provide an all-around theory of the causes of the Sixties, it just offer a couple of ideas to help explain why there's a consensus that the Sixties didn't start until after JFK's assassination. For example, Charles Murray's Coming Apart starts with a description of what life was like in America in the third week of November 1963. In various statistical measures, you can see inflection points in 1964-65.
This is important for assessing gradualist theories, such as Kevin Drum's not implausible idea that the long buildup of lead in the environment slowly undermined inhibition control. But we also saw a distinct hinge of a history in the mid-1960s that happened fast enough to raise doubts about purely gradualist theories being sufficient.
By the way, my instant reaction when hearing that President Reagan had been shot in March 1981 was, "Oh, no, hear we go again." Disorder was winning over order again. But then, the President didn't die.
I have this unprovable theory that the series of reassuring and humorously defiant jokes Reagan told between getting shot and going under on the operating table played some kind of weirdly powerful role in the national mood, even in why the Eighties turned out differently than the Sixties.