Baby boomers - came after the war, and just before the “pill.” They were the healthiest, best fed, best educated, most spoiled generation ever. They were the first Teenagers, the first to experience Rock and Roll, the first to have cars as teens, the first to “hang out,” the first to make significantly more money than their parents, the first to question the previous generation in any meaningful sense, the first to refuse to go to war, the first to indulge in “free love,” the first to use drugs in a big way, the first to “Tune in, turn on and drop out.” they brought music, drugs, philosophy and “spirituality” from the East. They rebelled against society and the Government - the riots of 68 for instance.
Before the baby-boomers there had been no fast food chains, no Woodstock, etc etc etc.
For the most part they were too rich, too educated, too busy, too indulged to pass on any faith to their kids.
Vatican II didn’t cause all these phenomena.