I think locker trucks might be the way to go.
Stuff would be loaded into lockers (no boxes at 50 cents each needed) on (or placed on) trucks (or trailers) which are driven to sites the customers can pick.
trailer lockers
Some of the locker cabinets might be swing (or slide) out to maximize the number of lockers.
These would be opened by like a Greyhound luggage locker is by the customer using a code.
All the lockers would have to be accessible. The stuff for wheelchair customers would be loaded in lockers accessible by a person in a wheelchair.
The trailers might be parked on site for two or three days before being brought back to the warehouse for restocking. A storage fee might be charged after so many days if the locker isn’t opened.
The system could allow for returns using an emptied locker.
They’re already trying to encourage that at every checkout to some degree, lockers at local stores. Your idea is the next logical step. Hopefully that will give other businesses. Amazon is always matching the lowest price of other places, and with their two day shipping it’s easy to use them instead of Chewy or other online stores. I try to support Chewy and other places whenever I can. I don’t want to support the big monopoly, they are already raising prices and limiting services. Walmart still has a 90 day return window so I use them often - they typically match Amazon’s price as well.