[s_fischer]

You're really comparing apples to oranges because the majority of Americans don't live within reasonable walking distance to a grocery store to begin with. Depending on where you live, it's not uncommon to take 15-20+ minutes to drive to the closest store.

With the return trip time + parking, you can see how it's much more sensible to plan your shopping ahead of time to optimize for the fewest amount of trips possible.

Even if you currently live in a borderline walkable area, there's a solid chance you grew up in an area where driving to the store was a norm and thus contributes to the decision to walk vs drive.

[epistasis]

Agreed on the design of most grocery store in the US. Most people can't stop in quick on a normal daily walk, because the inherent space-inefficiency of cars means a long detour to hit multiple stops, whereas with walking it's an easy in-and-out grab.

However, even when patiently explaining this difference, it is a mental leap too far to consider any change. Not only is it the physical design of the stores and car-only infrastructure, a lot of it has to do with package sizing and pricing structure, as another poster pointed out; smaller quantities get massive markups in US stores, for no good reason other than once they've got you in a store, you're fairly captive and they want to extract the maximum amount of money from you so that you don't end up elsewhere.

Until people experience it, and realize that having a five person family is no challenge at all for this style of life, it's hard to give them the picture.