Ah yeah, the perpetual Pleasantville scenario, how sweet. Once again, I'll give a detailled explanation why exactly this is bullshit beyond the mere reality-is-unrealistic mantra:
If you were born in, say, 1925, you'd live a childhood in the Great Depression, not really seeing a relief of it before the war, then engage in combat during the war as an (post-)adolescent and either be held captive or engaged in rebuilding, and only enjoy a post-war boom, depending on your country, from 1950-55 onwards when you'd be 25 to 30. Your formative years were full of hardships and now as you have some kind of rest, you want to enjoy your work and leisure and just left alone. These were the active adults that would form the 50s.
If you were born in, say, 1940-45, you may have grown up the very first years in ruins, but your formative years were simply hit by the swing of the economic miracle. And as you feel fed (and grow up well fed), you develop the cultural and mental resources to feel fed up and rebel. When you get into an active age as discussed about the fellas before, then you go in 1965-70 now.
These different days have been formed by completely differing mentalities. Hence we have a generation conflict and Pleasantville in the 60s is bullshit. Quod erat demonstrandum.
To add onto this, the 50s were an era of a return to normalcy. The world for the adults of the 50s had been, up to that point, largely a clusterfuck. There was an unprecedented period of economic depression where just getting by barely took a huge effort for most and people weren't sure if or when it was gonna end, there was a dust bowl, Fascism was rising in Europe, and there was eventually an unprecedented World War where everyone was involved by either helping the war effort at home or going over seas to face the fear and horror of actual combat. You had a collective generation go through that. And they licked it, and the 50s was their time to enjoy things.
The 50s therefore became a period of keeping your head down and enjoying the good life. The Middle class was growing, you could get a very good job with extremely good benefits and good pay across the nation, you could finally afford a car, a washing machine, and a television. In the political realm, Liberals became ok sitting back and letting Ike be Ike. Kids were growing up Spock babies, in this world where their parents were well off and the Middle class was at its peak. Teenagers, for the first time, had power in this Capitalist powerhouse that was the United States. And teenagers, as youth is want to do, started being rebellious, growing their own culture, dancing to rock n' roll, driving fast cars, and all that, or at least they thought the idea of all those things was sexy and alluring. That also adds onto the statement of BS of the ideal 1950s: there was more to Grease than there was to Leave it to Beaver. Leave it to Beaver was the ideal everyone of the 50s aspired to; an ideal is important to all societies, and at all periods of time, as it keeps order and gives purpose, but no one can ever attain it fully.
The 60s generation were the kids of the WW2 generation; the New Frontiersmen were the children of the New Dealers. They weren't spoiled brats, as many state to try to deride them, but they had not been worn on by the things their parents had. Their parents, for the most part, thought keeping your head down and just enjoying things in the age of Big Government, Big Cars, Big Benefits and Big Pay Checks was the thing to do. Their kids thought the thing to do was to make a difference and address the problems and ills of society, and not just sit back and think everything was ok and that everything you were told was the truth. When John Kennedy called these kids to volunteer themselves to the cause of making things better, I'm not sure whether his call or the generation's momentum to be transformative and to make a difference came first, but it certainly symbolized that this was a generation that was going to try to do big things to make things better and to change the bad to good and address the ills society had.
If you want a more conservative 60s, and one which resembles the real 50s more so than the Leave it to Beaver make believe 50s, I again think that the best you can do is make the period more peaceful. You cannot stem the tide; that generation had a rendezvous with destiny. But you can stop the bad that came, when things got too violent in the face of brutality and continued cruelties, and things go to extreme, and that healthy skepticism for some became an all out belief that men in power were evil or conspiratorial or total tyrants, and stop that belief in changing society from turning into, for some, a fanatic crusade that would be won through spilling the blood of those deemed evil.
That's really as easy as preventing Vietnam. Vietnam was like a crowbar which beat onto society and made cracks, and beat on the existing cracks on society till they got bigger and bigger, and then jammed itself into them and wedged them open.
I mostly think you get Flower Power and Hippies all the same, except none of the extremes and wicked, out of such a thing. Though maybe with some PODs you could stem the rise of the Hippies, make them a Beatnik niche, and send most kids into suites and ties and off to join the Peace Corps.