I've written about this in the past too. I believe we're hardwired to seek community and belonging, to form tribes. Our survival as a species depended on it. Now our families are spread out across the country or across the world, we live shoulder to shoulder with people we have no connection to, and the community institutions of days gone by don't really exist in the way they used to. And people have latched on to all kinds of other things to fill that void.
I would add that this has happened just as families became smaller and smaller. Was a time your average person had half a dozen or more siblings, a dozen or more aunts and uncles, and dozens of first cousins, most of whom you were reasonably close to in both geography and affection. I know a woman like that now. She has few friends because her family is where her life is at. Whenever she goes out, or out with her immediate family, to a play, shopping, to a cottage or cabin or whatever, it's with a cousin, aunt or uncle, sister, sister in law (she has 7) or mother and father. This is the way it used to be for most people through most of history. You had a huge, extended family that were part of your life. it was a tight-knit social circle. And now it's largely gone. People have one kid. Or maybe two. Or maybe none. Families are way smaller, and much more spread out. You might not even have any in your city or province - or country. That's a big void to fill.