When living in more walkable areas you don't feel the need to stockpile food as much. Often times you'll pass a grocer on your commute and can grab some fresh ingredients to use that night or the next few days. This can help save money too as you can take better advantage of short sales and have more opourtunity for "eat today" type discounts. Theres also the health benefits of active transportation. Unfortunately in most western society being able to walk to essential life giving food isn't seen as a priority in neighbourhood design.

There are electric cargo bikes that you can strap large panniers or containers to

Rad City cargo bikes

I personally don't ride anymore except for exercise, partially because I'm soft, and partially because there are not many safe paths/bike lanes to shopping areas

For distances you can reach within 20-30min on bike, public transport is usually about equal. Here in sweden (where public transport is kinda eeeeh) gettign to the stops is easy so long as you're not outside a town.

I think your problem is that you're applying car logic to non-car modes of transport: when you can reach the store in 12 minutes by bike there's little reason to buy a week's worth of food at once.

I usually buy food for maybe 2-3 days at a time, and not seldom i will just buy the ingredients for a meal literally a couple hours before, since it takes no time at all to go shopping.

You can also get a cargo bike which will honestly fit about as much food as people bring in their cars anyways. Same goes with a bike trailer.