Walkability is a matter of urban design. Only 20% of the US lives somewhere rural; 80% live in a city, suburb, or small town. We're taking about how the 80% shops.

Walkability is about lot size, density in general, mixed use development (putting houses near restaurants and shops), parking minimums, that sort of thing.

Walkable areas tend to be connected by public transit. Look at Amsterdam - to get to work, you might bike to the train station, take a train, then walk or bike to the office. You don't have to walk clear across the city; public transit connects walkable spaces.

Compare that with American suburban design, where shops are put far from houses, on ugly-ass loud dangerous stroads with comically oversized parking lots. You don't walk anywhere because anywhere you'd want to walk to is incredibly unpleasant to exist in. People will literally drive in their car to a walking path or a gym treadmill.