I think you're discounting the affect that big box retailers have had on rural and small towns in the US. They're often given tax brakes and other incentives to build and then they park themselves right outside city/town limits to avoid any sales or property taxes. They then proceed to drive every small business in the town out of business. As shops close down, fewer people go into town which the impacts other shops and gradually the entire town shuts down. To add to it, the big box retailers will often have leased space in the front of their stores where small businesses that they don't directly compete with can take up space. These businesses were probably the remnants of what remained in town but moved to where the people are.
You can see this in many towns if you drive across the Midwest. You'll see a "Welcome to <town>" sign, then drive through an abandoned town, then you'll see a "Thanks for visiting <town>" and then a massive super store with a filled parking lot.
The old-style downtown shop simply can't handle large products in a reasonable way. Since it can't, people get used to shopping at places that can handle everything.
Renting a van or getting the big box item delivered is so much more convenient. Commuting to work and running errands in a minivan is just so wasteful.
Larger vehicles like conversion vans and full size SUVs that don't seat anymore people than a minivan but get half the fuel efficiency and take up twice the space are on the other hand completely impractical.
Err... I think we have different definitions of what a big box retailer is. Big box is a reference to the shape of the building and not what it sells.
Wikipedia - https://en.wikipedia.org/wiki/Big-box_store
You could sell refrigerators in a small building. The selection would be very limited, and there would be a high risk of stock running out. The refrigerators out on the floor at a Home Depot or Lowe's take up more space than an old-style downtown store has. That's just refrigerators, and just the ones put out on the floor for display. Many more refrigerators are stored in the back, away from customers, and refrigerators are just one of many products.
It has nothing to do with the size of the product being sold.