I'm not suggesting we were or are anywhere near the limits of intellect--only that during the 60s and in the philosophical sphere intellect had apparently run into a brick wall. The chairs of philosophy the world over were at that time held by existentialists. This provided the intellectual climate for the disaster which was the cult-ridden 70s.
Mind you, the "spoiled brat" hypothesis has much to be said for it. The 60s generation were, for historical reasons, the first (for a while at least) that had the opportunity to really think about and challenge the current mores.
Neville B