Three days of food ingredients for two people isn't actually a lot, assuming you already have bulk staples (flour, sugar, rice, etc) in your pantry. I'm already including all the other incidentals outside of bulk staples: add occasional toilet paper rolls, paper towels, olive oil and vinegar, minor snacks, etc, and you get the one large grocery bag on average per trip. Maybe two if you're eating things that are bulky to carry (e.g. kale or something with a ton of eggs).

Like, come on. No typical two-person household is going through a full package of toilet paper and an entire mid-sized bottle of laundry detergent every three days.