From 1900 to 1965 Americans were more and more sociable. That began declining in 1966 and by 1980 we saw the first fruits.
Bowling leagues and PTA membership crashed, and church membership began to stall. It’s gotten worse ever since.
Main street churches are closing. Political Party membership is declining. Marriage and family creation is declining.
That same era, we became increasingly mobile. Children going off to college, marrying someone in that same college, not going back to their home town to live, etc.