I bought my washer and dryer at a Maytag store (while they were still around) and they had all models hooked up in house with utilities. You could actually bring in a load of laundry and wash and dry it yourself to see what it was like.
They also had a full kitchen with almost all of their appliances hooked up to test out. The usually baked cookies… so that made you want to buy something.
Pretty cool idea, but again, it was only Maytag appliances. If Sears, or Home Depot or something did that, the machines would probably be broken in a weekend and probably couldn’t control the customers enough to make it worth while.