Warehouse clubs are used to cutting costs to the bone. The exposed beams, stacked racks, and frills-free decor aren't an intricate theme. The warehouse setting is deliberately bare-boned to pass the savings on to end users.
It also doesn't hurt that items are being purchased in bulk for deep savings. And, naturally, the perishable nature of many of its items also makes them a natural choice for in-store, rather than online, purchases.
How popular is Costco? Well, it pushed through a 10% increase in its monthly membership fee -- yes, Costco shoppers have to pay for the right to shop there -- and customers didn't flinch at all.