that's a wrong dichotomy. There's no fundamental reason why 35 year olds don't socialize, or why our education system stops at 25, why we have no communal institutions, and so on.
The alternative isn't just between individualism and the family, what is needed is building out communities in ways that gives people the ability to connect in new ways that reflect our changes in work and living arrangements.
As the article mentions the UK has introduced a minister for the problem of loneliness. What we need is to put policies into place that develop new modes of social life and to expand the public sphere.
The nuclear family isn't really that attractive any more for a reason, so just asking to go back isn't really a great idea. People like the freedom that comes with having no or fewer children, being able to move, and being financially independent.
Can you expound on what you would propose. My experience is that clubs or meetups often don't forge all that close relationships. Another example I could think of which is more positive is co-ops where people lived in a door room type experience with community rules and chore responsibilities (cooking, cleaning, maintenance). But I think many adult American's would think of a co-op as to close to a commune.
For younger people I think coops are a great thing too. In the US implementing policies that discourages single family housing and promotes closer connection between workspace and living space I think would help. If you live and work in walking distance of your chess club going there is more likely compared to someone living in the suburbs.
For communities there's also time banking which has gotten a little attention in recent years. Essentially paying people in a special currency for reciprocal help in their local communities that can only be exchanged locally, and everyone earns the same based on how long they work. Basically an egalitarian approach to fill in the gap where markets are too anonymous to provide meaning or where they don't exist at all.
And then I think government and companies should do much more to promote education for middle aged and older people. And not just online learning, but physical interaction. In my experience educational institutions are some of the best places to make new social connections.