On the Movie front I would say that three marking places would be
Before star wars
Before CGI
Before Toy Story
Actually, the Big One that changed the US movie business forever was Jaws. It started the big summer blockbuster trend. People went to the movies, in large numbers, in the summer? Wow. In many places you actually had a choice of theaters in you city where you could go see it. Unthinkable!
It’s still #7 all time adjusted for inflation. While, for example, GWTW is #1 it didn’t really change the movie business.
Absolutely right about Jaws!
Another cultural thing: The Twist. In itself, it was a fad, but, correct me if I’m wrong, it established non-contact dancing/dancing without a partner at all.
Sexual intercourse began
In nineteen sixty-three
(which was rather late for me) -
Between the end of the “Chatterley” ban
And the Beatles’ first LP.
– Philip Larkin, “Annus Mirabilis”
On the same topic, I’d offer the transition to sound after The Jazz Singer. Although there were earlier experiments with sound, that one “opened the floodgates”.
Also, the transition from the traditional movie studio system that was in place up until the 1960’s. Again, there were earlier minor changes.