Of course people's situations vary. Some households have more people or some families don't have a car.
However, the point is, are people doing as few shops per week as their household could manage on if they planned carefully?
If you have to walk to the shop and carry it back, you might well NEED to go 3 times. If you have 8 people in your house, your fridge might not hold enough food for a week and you might NEED to go more than once.
However, people with decent sized fridges and freezers and transport often seem to go several times. I'd suggest that some of them don't NEED to go so often but could manage with fewer visits if they planned ahead more and also if they accepted not instantly having every item they want right now, but just added it to the list and waited until the next shop. They could make fewer visits if they discussed as a family and individuals within it didn't pop out for an ice cream or a newspaper and co-ordinated themselves.
I think that lots of people have tried really hard to reduce their visits to shops and made some reasonable and manageable sacrifices in terms of not always or instantly having everything they want, but still having plenty to eat. However, some haven't really made adjustments to the way they shop usually - just thinking about a day or two ahead, and being willing to go to shops pretty frequently.
There is a difference to needing to go more often than once a week and just choosing to. Fancying an ice cream, or not planning ahead and so frequently forgetting items and then deciding to go and get them, or not being prepared to make any adjustment to what is eaten or to wait a while for specific things until the next shop, just seems a bit lazy and actually careless to me. It is the shop visits where human co tact happens even with social distancing.
If your household makes 6 visits to the shops between them, and another makes only 1, the latter has less chance of catching it but also less chance of spreading it to shop workers or other public. But I think in reality lots of people are starting to put their own convenience ahead of the impact of the spread of the disease.
I'm not saying no-one should go more often. Some people need to. But are people really only going when they NEED to and as infrequently as possible - that's the Q.