Not by distance. But imagine doing it on a 0.5 meter strip of poorly maintained concrete slabs, with the occasional light post sticking up and forcing you into an even narrower space or onto the uncut grass. Now imagine that strip is surrounded by nothing interesting to look at, and just a couple meters away, there is a constant stream of large trucks going 100-120 km/h beside you. And every time you hit an intersection, you're going to have to prepare to cross 6-8 lanes of that stream as drivers who don't expect you to be there have their eyes glued to the green light they have as they turn into the crosswalk that the signal is telling you is safe to cross. Now you arrive at the parking lot and the last 200m don't even have a sidewalk, you are just walking in the road through the parking lot as you pass empty spot after empty spot because an engineer in the 60s pulled the wrong number out of his ass when guessing how many spots grocery stores should be legally reguired to build. Oh, and the grocery store is structured for people who are buying in bulk, not for someone who just wants to grab a couple days of food that they can carry while they are walking. Yeah, it's no less physically possible than the 800m stroll you were envisioning, but it becomes pretty clear pretty quick that nobody in charge wants you to do what you are doing in that environment.