You'd have to avoid WW2. The Baby Boom and disruptions of the war, social, economic, everything really, caused the major changes of the 1960s as the children of the WW2 generation or least those born during the war were reaching their teenage/twenties and driving a cultural backlash against the culture of their parents. Part of it was inevitable, but the WW2 generation returning home and trying to seek normality and creating a stuffy culture of rigidly enforced norms created an outspoken youth culture. Part of it too was a lot more kids going to college than ever before, unheard of prosperity (the go-go '60s), the Cold War and Vietnam, demands for racial justice breaking out into the open thanks to media allowing people to see the realities of the Jim Crow South, as well as the WW2 generation's experiences of what White Supremacy and Racism meant in Europe spreading to the next generations in their formative years and taking to heart.
Without WW2 culture doesn't get revolutionary, it remains more evolutionary due to society staying intact during the 1930s-40s and on as well no Cold War. There aren't the same dramatic actions and reactions that reverberate, while without the shock of the Baby Boom the youth of the 1960s-70s aren't such an overwhelming part of the population relative to everyone else. Demographically the Baby Boom generation was a giant distortion to country and gave the youth an outsized voice just as media was becoming modern and prosperity meant TV was widespread and youth culture could be commodified in a way it had never been before. Then add in the Vietnam war and the clash of generations and cultures that resulted, with the large youth population getting organized and radicalized by the fear of having to go fight and die in a horribly foreign war that could be seen in all its gore on the nightly news and it was a perfect storm of events that produced an explosion in the 1960s-70s.