What people forget is everyone is in a different situation.
I'm fortunate. I have a grocer who sells loose fruit and veg, a Tesco, an Aldi and allotments all within walking distance but I have pre-payment meters and no car so cannot do big or bulk shops.
I would, when I was able, walk down to Teso at 9 pm/10 pm and have a look at their reduced section but that relied on me not being at work at 9/10 pm and the kids being old enough to be left home alone for an hour. What I could cook with what I managed to get on the days I could get there depended on how much gas I had and how many hours I was working the next day.
There were times when we struggled for food when I was working in an apprenticeship role Mon to Fri 9-5 and then working nights in care to make ends meet. I would sometimes be on shift for 36 hours straight. Those days I ate pizzas even though I do not like pizza because the thought of having to walk to and from Tesco with heavy bags and then stand in a cold kitchen cooking after being awake for almost 48 hours was just too much to bear. I lived mostly on chicken nuggets and cheese garlic bread for the 2 years I did that.
Other times I have worked split shifts and could cook between shifts but couldn't get to Tesco until midnight (if I had the energy at all) when most of the stuff had gone.
The times when I've been unemployed have been easier than the times I was working and in poverty but you need to remember a lot of people in poverty are working, studying, or disabled, and not everyone has a big supermarket within walking distance or is physically able to walk/carry home shopping.
Although, at no point have I ever had to resort to sardine pasta or peas and potatoes. Beans and jacket pots - yes, omelets with whatever fresh or frozen veg I had to hand, yes, but plain potatoes and peas, no. I would take a pizza over a plain jacket potato despite liking jacket potatoes and hating tomato-based pizzas.