Aside: I live in Los Angeles and am trying out Amazon Fresh. If anything, Amazon now offers me an almost-confusing multitude of ways to have products delivered to my house. I can Prime things for receipt in two days. I can subscribe and forget. I can Fresh things for next-day delivery. I'm not an Amazon fan boy—many of their services frustrate me in a variety of ways—but they have delivery pretty much mastered versus everyone else.
At any rate, I was truly sold on Amazon Fresh the day I started having some issues with my PC. I logged on in hope and ended up ordering a CPU and a Motherboard to be dropped off at my door with my milk and eggs before dawn the next day. Incredible.
I laughed at your mix of computer equipment and groceries, but that's exactly it: you can have a wild variety of things delivered as if they were groceries. I was most amused/bemused by the weapons selection.
To each his own, I think this is the ultimate lazy man's service. Get your ass out to the store and when you're back, mow the lawn.
Unlike shampoo and other bulky disposable products, razors are quite tiny.
Although I'm probably not thinking of a few things, I do buy basically every nonperishable in bulk. I buy paper towels, toilet paper, double-edged razor blades, toothpaste, laundry supplies, and shower supplies at most twice a year. It's not that hard as long as you find SKUs that you like and have somewhere to store them (and I live in a tiny San Francisco studio, so most people should have plenty of room).
Consider the same question for basically every nonperishable you purchase - why are you not buying in large bulk and saving? I can think of a dozen items I could buy in bulk and save money on that I currently don't.
Actually, now that I think about it, why don't I buy in bulk? I totally could. Why don't people in general buy in bulk?
Anyway, it's the same answer for your toilet paper as it is for your razors, or your shampoo, or your paper towels. I don't apparently know that answer, but I assume that's why people don't do what you're saying.