I guess in the US may be different, but in Europe people usually make the weekly food shop either during the week (after work or before work) or on Saturdays. Almost everything is closed on Sundays. Also, what do you mean by built-up areas? In Spain, Germany and UK (countries where I've spent most time) you can get to almost any place with public transportation. Maybe they come once an hour, but for planned shopping this should not be a problem.
“You can get by basically anywhere in Europe without a car. Sure, you might have to walk 20 or 30 minutes or so (one-way), but the wear on your shoes from that is absolutely negligible.”
Ask yourself whether you agree with that statement, because it’s quite different from what you have been presenting.
I do. The original comment talks about living without a car. You may need to walk 20 or 30 minutes to get to the public transportation to get you to your destination, and this is what I have been presenting all over.