[Qwertious]

If you run a business selling a niche amenity, you need to do so in a city because in the country you won't have enough customers nearby.

End result: cities have more fine-grained amenities. People who want more amenities live in cities.

[theamk]

There are? I see the opposite trend (at least in US East Coast) - cities only have generic amenities, while all the unusual stuff is in the suburbs, where the the land is cheap.

For example, let's take a relatively common hobby of sewing. The two stores in downtown closed tens of years ago, and the only ones left are in the suburbs, unreachable without the car.

I think at this stage, the only advantage of city is bars, restaurants, and expensive clothing/jewelry. If you like something else, you are better off in suburbs with a car.