My theory is that unhappiness is not all the various factors other people are talking about, not fundamentally: not money, not neighborhood design, not living in the city vs. living in the country -- its a deeper spiritual problem.

If you really want to understand something you need to integrate all the evidence, of course, and not just the parts that support the easy conclusion.

It's under-discussed, because we, the technocratic class, have no tools to measure it and not much language to talk about it.

It's the combination, young people are supposed to be doing fun stuff, and the idea was you needed to live in the city to do it. And you went for a less desirable living situation because it was cheap but near the fun stuff which was also cheap. Now the amount of fun stuff in cities is drastically reduced, it costs way more to live and the fun stuff is unreasonably expensive.

Just going off of my personal experience, the same highrise I used to rent is roughly 50% more. 2k to 3k. Two of the entire nightlife districts that were very close are completely gone, torn down and converted to high rise buildings with very boring very expensive ground level retail. The few places that remain are expensive, $12 for a drink is normal, maybe a draft beer is $8. In contrast, I could go out any night and find $2-3 drinks. $5 pitcher of beer, and get a solid meal for under $10. Almost all of the sports leagues at the park next to the highrise are gone. The only festivals that can afford to operate depend on high ticket sales and drawing people from out of town which makes huge annoying crowds.

And I'm not even going back 10 years, this was like 7-8 years ago. If you go back to like 2010 things were even cheaper and more fun.