Without power my supermarket also can't store its frozen or refrigerated goods safely, so that's about half of the store and notably the half which has mostly things shoppers might want immediately, if there's a disaster and I can't buy
dishwasher powder I don't care, if I can't buy
food that's a big problem - and much food is refrigerated whereas dishwasher powder is not.
Next, it can't light the store. In mid-summer you can probably use the parts of the store with some natural light for most of the day, the rest of the store is too dark to allow customers, as is the behind the scenes re-stocking etc., they also can't open the delivery bays which are electrically shuttered, and they can't operate the doors, the escalators or the elevators.
Now, I live in a major port city, so obviously in reality the power isn't going to stay off here, not for days, at home I've had a handful of short (< 2 hour) outages and one serious (~4-8 hour) outages in maybe 30 years living in this city. Anywhere with multiple supplies or backups is going to have even less problems.
I can buy that things are different in rural areas, but it seems to me that mostly you need backups for other reasons anyway, and both electricity and IP are great in those terms because they're so fungible compared to conventional backups.