Wal-Mart's bottom line is making money. Nothing wrong with that but don't delude yourself that it's about the consumers.
Consumers seem to think it is. They really don't care if Wal-Mart makes money for its shareholders at the same time.
It seems to me that they've discovered that the best way to do that is by bringing goods to consumers at the lowest possible price, thus making happy, satisfied consumers. Whether it's their ultimate goal or not, they still have to make their customers happy to in order to get the thing that is their ultimate goal - having satisfied customers is a necessary (but not sufficient) condition for making money in retail ;)