I agree that cars are often used to go to a supermarket five minutes walk away - and to drive to the gym and pay an enormous subscription to get some exercise. Not having one at all has its drawbacks, though.
I have no car and walk or bus everywhere (taxi very occasionally) It is 5 - 8 minutes to a small Sainsbury's or a Co-op. BUT it is then ten minutes uphill home again, carrying my purchases. I limit myself to buying what I really need and carrying it in a backpack.
Or I can catch a bus (from outside Sainsbury's) and be at a large Tesco in another 10 minutes. That tempts me to buy a lot more, so I have even more to carry home.
If I plan ahead, I take a shopping trolley, and fill it up. Have you tried humphing a packed shopping trolley on and off a bus? It is heavy and unwieldy. If I have just the backpack, and it is packed full, it has to be lifted off to sit down, and on again when I get off, without clouting anyone round the head. Several full plastic carriers are even worse, and they cut into the hands and strain the shoulder muscles too.