I believe the greatest factor is community. In my experience wealthier people, and wealthier areas, tend to have less community and weaker interpersonal bonds because they do not depend on one another to the same extent that poorer people do.

When your neighbor needs to borrow a tool, you need to sleep at a friend's place, or you give a friend a ride to work you're building relationships. The web of relationships between all the neighbors in a community forms a culture.

When people become wealthier they don't need to borrow tools because they can buy their own, they don't need to crash at a friend's place when they can stay in a hotel, and they don't need a ride to work if they have their own transportation.

In my experience some of the isolating effects of wealth accumulation can be mitigated with infrastructure that increases the inter-dependence, trust, and fraternity between neighbors. A few examples are walkable cities, cooperative organizations, social clubs, public parks, etc...

really don't like when people romanticize poverty but if I had to guess why people say that poorer countries feel more authentic it's just due to the fact that it's different to what they're accustomed to and this could be replicated by just going to the poorer areas in their own country

Probably because people of poorer countries actually have culture that extends beyond capitalism.

If I were to choose but one thing: car-tailored city planning.

Pretty sure because it's their lives have not yet been greatly affected by modernity and consumerism

There's a difference between a store built from wood and a store built from plastic that's supposed to look like wood. It breathes a feeling of simplicity, and not profit based optimization. It's something new.

There's a sauna I go to with some pretty dumb features, and the entrance fee is way too cheap to be profitable. But I love it because it seems to not be built with profit in mind.

Family owned small businesses.

The more development (be it good or bad), the greater the distance to "authenticity".

Reproducing authenticity is therefore as (im)possible as undoing the development