Personally, I feel Wal-Mart is bad for the economy. However, I understand enough to realize I have absolutely no clue when it comes to economic theory.
All I can see are the results of how they treat people. I am not a fan.
Part of me feels I was born about 2 generations late
I am much more of a small town, main street sort of guy.. I'd much rather pay more to buy from someone I know in the community, who helps support a lifestyle I enjoy. I still try to do this here, but not nearly as much as I'd like.
I also feel that many smaller companies, while certainly less efficient in most cases, are orders of magnitude more resilient than huge monolithic corporations. See the banking crisis for this - you don't see too many small credit unions who didn't farm out loans going bankrupt or asking for money - they made responsible financial decisions and while hurting, are still fairly healthy today. When the people selling the product (in this case, loans) don't have to stand by it - then you get into the scenario we have today of effectively scam artists running things.
Sorry.. went off topic
I think you will find, that Wal-Mart takes a loss on the staple foods that grab headlines/attention such as Milk, Bread, etc. This gets people into the store because it is "so cheap!!!" and then they can charge higher amounts for other products when you don't notice.
It would be interesting to take a standard shopping list containing a nice mix of milk, cheese, meat, fruits/veggies, prepared foods, etc. and buying the exact same quantity/brand (when possible) from both Wal-mart, and your local discount grocer (here it would be Cub Foods - not something fancy like Wegmans or other "higher end" grocery stores). Also of course be careful a "box of pop tarts" or whatever is the same from both stores - e.g. verify quantities
I think you will find the totals are pretty close, far closer than you may think.