Believe it or not, we do have cities in the US with walkable areas :)

I am in Madison, Wisconsin and we have a number of areas like State Street where walking is the norm: https://visitdowntownmadison.com/

By and large this is not the case but it isn't as if it's unimaginable what it would be like.

I've visited Madison and really liked it, but I wouldn't compare it to the walkability of any European city