In his influential book
Bowling Alone (2000), Robert Putnam showed us that in the U.S. all forms of community have gradually been going out of fashion since the mid-1900s. As the title implies, people no longer bowl in leagues, but also people no longer join clubs or organizations (like the PTA), no longer attend religious services, no longer have dinner parties with friends, no longer live near extended family… I could go on for a while, but you could also just read the book or watch the recent Netflix documentary based on the book,
Join or Die.