A reasonable length survey will never "paint a full picture". Maybe what they're trying to show is that there are a lot more people who value walkability more than is currently assumed. In most of the US you can either chose a super high density walkable area in a condo tower or a house in a car based suburb. It's possible to design neighborhoods that are walkable and can provide a reasonable amount of private outdoor space, and what this shows is people would be willing to pay for it!