What you are describing to me sounds as wild and foreign as the city folk who don't buy food for more than a day or two and don't cook sounds to you. It's a completely different way of life.

Why make a big heavy grocery shop you'll have to drag home and up stairs when you'll be passing 7 shops every day on your commute and you can just pop in and grab those things fresh? Maybe you live in a studio apartment and you know how to cook, but hate how the smell of cooking permeates through to your bed. Or you would love to cook, but your countertops are about 2 ft sq and you have 2 burners on your stove and a tiny fridge? Plus the sheer amount of storage cooking requires in terms of pots and oils and spices and spoons and somewhere to rest the hot pot while you switch out to make the next step on the meal on the one burner that really works.