Good question. Maybe this is part of the answer. WalMart is planning to open some 60 super-stores around the country that have everything from tires to groceries. In some parts of the country these stores have already killed off several supermarket chains because they deliver products at about 14% less than existing chains. Cost-cutting competition against these stores is a big part of why grocery checkers are on strike in California. They're being asked to forgo raises for 2 years and accept higher medical care premiums.
Anyway, it doesn't strike me as beyond the realm of possibility that lobbyists for Safeway, Kroger, Albertsons, etc. are putting plenty of pressure on the Justice Department to find any irregularities in the way WallyWorld does business. As a footnote, Oakland, CA where "Moonbeam" Jerry Brown is now mayor, has just outlawed these big stores through its zoning laws.
I have to admit to some nostalgia for the old Main Street, with all the different (though expensive) specialty stores- but I must admit that we shop at WAL-MART and SAM'S Club to save money (I just saved over $200.00 on my snow tires over what the local tire store wanted for them- nostalgia be damned!)
Is this ultimately good for the economy and the country? I really don't know. I do know that protectionism has NEVER worked as a national policy, and it probably won't work at the local level, either.