I'm not sure that anyone could define it yet, but it would have to start with breaking away from the 20th century philosophy that's still very ingrained in most of society. The defining feature of that philosophy is that self-actualization and the individual are almost deified.

I actually think a lot of that was fueled by post-World War II prosperity in the US, and ultimately the rest of the west as the century got past its midway point. Globalization in a way is normalizing that "peak" and I suspect that, in addition to the corrosive effects of narcissism at scale will cause some sort of reaction that looks very different than 20th century teenage rebellion and extended adolescence.

For a theoretical example of 21st century life, I could imagine multiple generations sharing the same home, as is already the trend. That may seem very old fashioned but I see it as more post-modern as it will be mixed ad hoc with other more future forward conventions (for better or worse). Maybe some of those living in the household are gig economy workers enabled by technology for instance.

That last paragraph screams of societal failure to me. Gig economy workers who live with family out of necessity, the only work they can get being lowest common denominator "go here, get thing, take here" work, paid peanuts with no rights.

There's a reason the individual is the primary unit in western societies - we saw and can still see societies structured to put the group, the commons or the country first. They committed atrocities against masses of individuals in the name of the group. No thanks.

Yet depression and isolation are at an all time high. Who's to say strengthening family and community bonds would result in a failed society? It would certainly have negatives and positives. It's only purely negative when viewed through the lens of individual economic achievement (which may not be possible to the level seen post-WW II in the west).

> Who's to say strengthening family and community bonds would result in a failed society?

Nobody, but getting there by forcing everyone together because it's no longer possible to afford to do otherwise seems to be a good indicator that something has broken.

> It's only purely negative when viewed through the lens of individual economic achievement

I'm 41, I moved out of my folks place when I was 18. My life would have been quieter and poorer if I had had to stay in their house for the last 23 years, following their rules, and it would have driven me insane. I lived in shared houses for several years, then moved to my own place, now live with my partner.

It's not just about economic success, it's about having your own space to be yourself and live life the way you want it.

> (which may not be possible to the level seen post-WW II in the west).

Oh rubbish. Endless growth may not be possible or even desirable, but being able to make your own way in the world is not over, nor is it likely to be any time soon.

--edit-- I do understand that, for instance, owning property is much harder in many places now than ever before, I think we have work to do as a society to mitigate that. But I also think that perhaps we've over-centralised on a few desirable, expensive cities (in the UK, where I live, but also other western nations). A re-balance by distributing the wealth-generation around a bit more would help.