It’s much more complicated than that.

In a society where everybody is already driving to school, work, food, shopping medical appointments, gas stations, kids sports, etc this is just a marginal additional trip for the consumer.

Having redundant logistics companies (USPS, FedEx, UPS, DHL, Amazon, WalMart, Uber, etc) all making deliveries optimizing for something other than _minimum distance traveled_ means they aren’t optimizing for the same thing the consumer would.

Also, there is the game theory aspect. When a consumer mentally thinks they can just make a $5 purchase on Amazon and get it delivered the next day “for free”, they are less likely to take care to shop in bulk / batch their purchases. Nobody goes to CostCo for a $5 trip (except for the weirdos who go there just for the hot dog / pizza lunch). I personally don’t like the hassle of CostCo for less than a $200 shopping trip.