I thought about it - even with a 100 convenience score, I think I'd find it incredibly inconvenient to have to get groceries without a car. Someone living single - sure, you could get away with a trip a week, maybe. But, every time I get groceries, it's multiple trips out to the car to carry everything in. Plus, like yesterday - I purchased a super-jumbo size pack of toilet paper that was on sale. That single item is an entire purchase for a walker. Thus, they have to buy in smaller quantities and can't realize the savings of buying in bulk, else, they have to make a shitload more trips.
I partially agree with this. I live alone and shop for groceries once per week, by car. Even on the trips when I buy bulk items, I can usually get away with only 2-3 trips back and forth from the car to unload everything.
Now, if the grocery store or other markets were on my way home from work, I could just stop by the store a few times a week as I walk, and buy smaller quantities of exactly what I need. This is a pretty common method for a lot of Europeans.
The idea of buying in bulk is really a North American phenomenon which encourages car use and overconsumption. Even if it's slightly more expensive, buying smaller quantities of healthier, higher quality food is better for you anyways.
By living in a higher-density neighbourhood where you can walk to many amenities and commute using means other than your car, you can cut down car usage a lot, without giving up your vehicle entirely.
For instance, I'm able to commute to work by transit, bike to the gym, and I can get downtown and to other neighbourhoods by transit (rail) to socialize with friends. All I really use my car for is running errands on the weekend, visiting my parents and driving to the local mountains or parks, which is more difficult on transit. I still have my car, but I only drive about 6000-7000 km a year (4000 miles). I think it's a realistic compromise.