Only because stores that have large parking lots are in cheap land areas that are hard to reach by bus, bike, or anything except a car really. Where one can comfortably walk to a store, giant parking lots are awful.
replyIndeed, and in defense of Costco, you don't go there by bus or bike anyway because you'll be coming home with 200 pounds of stuff. Target is different for me. I hop in there for one or two odd things that I need, likewise the nearby grocery store. A side effect is that I don't waste money or space on stuff that I don't need, because I can always hop over there in a jiffy if I do need it.
replyIn lieu of Costco, my family buys all of the big and non-perishable stuff at a giant discount supermarket that's closer to the edge of town, or at least it was until other stuff got built up around it. But we try to minimize the number of trips.