Cities are economically advantageous for a reason.
I don't think people are suggesting we make cities less appealing. Rather, people are advocating for measures that make cities more livable, such as investing in mass transit and reducing the amount of space inefficient car infrastructure and usage.
And yet a lot of major US cities were losing population into the late 90s. And some (like Detroit) never really recovered. Even if there are various reasons to live in an economically prosperous region, lots of people have no interest in actually living directly in a city.
Because US cities became slums, and rich people lived in the suburbs. In the rest of the world the rich people live in the cities and the poor people live in the suburbs with long commutes, there is no reason USA can't work like that as well.
Except that the US has the space and many/most people don't choose to do so--at least full-time.
Even in places where the wealthy had to live in the city, they often had summer places (in particular) elsewhere.
If you don't need to live in a city, for a lot of people (including myself), it makes a lot of sense to live elsewhere and go in for things.
I could live in a city but I have no particular reason I have to. So I choose not to at this point in time. Which is true of most of my friends as well.