It all started in larger cities with the Supermarket. Everything they could want for groceries was all in one place waiting for them on the shelf. Now it is the Super Wal-Marts in nearly every small city across the US. Everything they want for the house inside and out can be found under one roof waiting for them including groceries. People no longer have to stock up on anything. People will go there 6-8-10 times a week to pick up something they are out of that day.
It is the difference between a consumer mentality and a producer mentality in America.
(Paraphrased from an Amway presentation) Fortunes have been made relying in the fact that people will buy neccessities today use it the same day and go back again tomorrow for more.
It is to convienent for most people to go to the store to get it and let the store keep it in stock rather than to have extras of anything around the house.
Some of us have grown up hearing "Waste not , Want not !"
Others grew up hearing "Spend it while you have it !"
They do it because they haven't been affected badly enough by their buying habits.