This is assuming "mom and pop stores" are beneficial. We certainly like them when driving through picturesque small towns but I know a lot of people living in those towns that prefer an efficient supplier. They understand what they lose but prefer to save money on their shopping trips.
Walmart not only sells merchandise cheaper than "Mom and Pop", they almost certainly pay their employees higher wages than Mom and Pop ever did. They also have a 401(k) (fully-vested after only 7 years) and an education program that covers tuition, books, and fees for majors of interest to Walmart (e.g., IT and supply-chain management).
The opportunities for advancement at "Mom and Pop" were pretty much limited to "Son or Daughter". By contrast, the current CEO of Walmart (annual compensation $22 million, net worth > $100 million) started working there as a summer job in high school, unloading trucks, and has never worked anywhere else.
