I think the system creates the people, and to then turn around and say "it is the people that failed to get along" is true but also lacking in explanation.
Since the 60s, new ideas, call it an open-minded spirit of social exploration has swept the West. It has resulted in a spirit of individualism; consequently people have indeed grown more unique and probably more isolated simultaneously.
We can't realistically expect them to then come together and have a comparable amount of, say, incompatibilities with their partner as we could of people 30 years ago. They probably also meet less people organically. More differences, fewer opportunities to meet those with commonality. It's bleak.
Yet what I see pretty routinely are people struggling to meet the tradition despite changed circumstances, while larger society still incentivizes it despite it becoming an increasingly poor fit for the people. Colorful anecdotes aside, which imo are simply representative of that pattern, a social institution should actually serve the people.
As someone who has been part of the cultural changes you mention, I have first hand experience in the American aspect of those changes.
"...It has resulted in a spirit of individualism; consequently people have indeed grown more unique and probably more isolated simultaneously."
Just not true. Any spirit of individualism has been around for decades, centuries and likely much longer. The opportunity to express oneself more freely has been growing steadily since the WW2. The boomers latched on to that and carried the flag forward in very public and influential ways. They had the numbers and normalized it. Affluence and new media spread it around to all. Nobody "became more unique." The forced social conformity of prior times collapsed. Social isolation didn't get going until broadband went mainstream and it was easy to just stay home to be entertained. If you want to put a hard date on it, I'd go with June 29, 2007. But there could be others.
"We can't realistically expect them to then come together and have a comparable amount of, say, incompatibilities with their partner as we could of people 30 years ago. They probably also meet less people organically. More differences, fewer opportunities to meet those with commonality. It's bleak."
It is pretty clear why people get married: lust, money, companionship, and love. Why they choose to get unmarried is more complex and after the fact of being married. Generally speaking, they cannot get along. Each person in a marriage brings their life story into the marriage and those stories often do not mix well unless both parties are willing to work it out. So, is the problem today that our life stories are more incompatible than in the past? That people are less willing to "work things out?" That our consumption of media orients us towards a view that marriage is a short term proposition?
We do know that long term, close emotional relationships with companions/family is a fundamental need for humans and when those are lacking our mental state is less healthy. In most societies institutionalized marriage is/has been a way to foster that and build families. What is your alternative?
