I honestly can imagine that Costco is overall more efficient than Amazon, especially for people who do shop at Costco. If there's no Costco closeby, its more likely that the individual humans will shop elsewhere or somewhere more convenient.
there are people who regularly go out of their way to drive to their favorite store for like 1-2 special items, people bring their dogs along on trips for companionship and leave them sitting in an air conditioned idling car while they shop
individuals are irrationally inefficient in dozens of ways that large businesses root out, for better or worse
No one is driving an hour out of their way for groceries.
And even the F150 truck example: if they are driving 30 miles to work, but 10 miles to Costco and 25 miles to home (Costco being 5 miles out of the way.), that F150 going 5 extra miles is more efficient than a Prius driving 25 miles from a Costco to their home.
Integrating routes throughout the day that matches your driving habits is a basic adulting task that everyone does, and has reasonably high efficiency.
> that F150 going 5 extra miles is more efficient than a Prius driving 25 miles from a Costco to their home.
but that's not what's happening, Amazon isn't driving a Prius to your individual home then back to the warehouse... it's driving to a hundred people on an algorithmically optimized route. They do this because efficiency at scale makes them more profit.
Individual people make inefficient preferential decisions all the time, because the incentive to measure and improve these things is too low to bother on an individual scale.
The vast majority of those Amazon packages are for one thing. When the inefficient pickup truck comes back with a whole weeks worth of $200+ groceries, that further increases the efficiency of the home buyer.
It's unlikely that a daily commuter would go to Costco for just one gallon of milk or a few batteries. But I know from my Amazon deliveries that single items are delivered all the time.
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Anyone grabbing just some extra milk or toothpaste is likely grabbing it at an even more convenient store, like 7-11 (mostly because you can't buy one toothpaste at Costco lol).
Non-perishables are fine on a single-unit purchase because again, they're not just going to your house, they're going to dozens in your area every single day.
I know where you're coming from, but there's a reason this whole model exists, and it's not because it costs more.
Costco shoppers buy a lot at a time. Because Costco forces you to buy 4 tubes of Toothpaste, 24 eggs (or 60 eggs), minimum 1 gallon of milk (no half gallons or pints), and like 20 lbs of rice / 10kg for the Europeans who havent been here and like 3000 meters of plastic wrap.
For Costco, the efficiency is the shear size of the shopping carts and shear mass of the goods sold at a time.
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You literally can't buy only one bar of soap or one toothbrush like you can from Amazon.com or other stores. There's efficiency here because of simple mass.
In contrast, I can look out and see the Amazon packages in my neighbors doors. It's all single items across the neighborhood.