1km or especially 2km is not in any way a reasonable walk. It is just barely reasonable for a healthy adult in good weather, and still tedious. I personally find that mid-density is the worst of both worlds, and not just in this regard... I used to live in downtown Vancouver BC and it was great to have everything I use within 200m, now I live in the kind of area you describe (semi-urban detached houses) and I almost always drive, just as if I lived in the woods. In fact, after COVID I wish I had originally moved to the woods!

1 km not a reasonable walk? That's about 1300 steps for me, a fifteen minute dawdle or ten minute brisk walk.

I can walk to the nearest shop fill a small rucksack/daysack with the day's shopping and be back home in 45 minutes without hurrying.

Most people would prefer not to walk 25 extra minutes (1km two ways of standard 5kph ped speed) every day just to buy food, even in good weather. When it's raining, snowing, etc., or when they are old, have children with them, are not so fit, even more so. Many people have things to do with these 25 minutes, too.

When I used to buy groceries daily on foot, it took me about 5 extra steps, one way, to get to the store from the sidewalk that I was already traversing from the bus stop that was 150m from my apartment... and then I carried them 100m to said apartment. That is the density that most people can accept when they think about "walkable"... These days I pick up a week's worth of groceries (impossible to carry, and I say is as a backpacker) on my way from the gym, or occasionally in a separate trip that takes the same 25 minutes round-trip for travel, except I do it once a week, or could do it even more rarely. And if you drive, it doesn't really matter if the store is 2-3km away on the street (which it is), or if it was 10-25km away on a highway.

It's not 25 extra minutes. I just do it as part of going for a walk. We did the same with the children when they were too small to leave at home.

Ok, apparently for this situation to be livable you not only have to be healthy AND the weather has to be good (you don't go on a walk with kids every day when it's 100 degrees out or when it's blizzard of rain), you also have to have plenty of time for daily walks :)

Again, my point is, for most people, in most circumstances, 1km is a borderline unreasonable walk, and 2km is absolutely unreasonable and not "walkable" in any way. Sure, for some people in very special circumstances (and climates, or times of year) it might work out, but that is not a good basis for policy.

Also frankly it's just an inferior quality of life when your walk is to the grocery store thru dense burbs... I happen to have 2 large-ish parks nearby so I walk there, but not every day and in any case neither is on the way to any grocery store. I would never just walk around the neighborhood - instead, if both were 1km away, I'd drive to a park or a hike if I had to... then drive to a grocery store.

I never posited a false dichotomy, I just said there’s a spectrum of conveniency and that it is related to density. The more density the more things closer, by definition, though; and the bigger the demand for real estate, so people end up with less space due to physics and pricing.