First of all, you guys are pretty off base about Wal*Mart policies in general. Yes, they do some of the stuff mentioned at some stores, but as a whole, the company is not the evil devil that some make it out to be. That Wal*Mart Movie has been shot to heck by experts...all the examples in it are real, but most deal more with local stores that break laws/subvert the intent of the law, than the actual company. When you have as many stores as Wal*Mart, you will have bad managers at some. I know about a dozen people who work at Wal*Mart, both as clerks and in management. They all have awesome benefits, comparable to what state workers make in PA (which are some of the best benefits out there). My one friend needed massive surgeries on her arms, and her mom works at Wal*Mart, and it was ALL covered under their insurance. There are a lot of misconceptions about Wal*Mart...even look at what zambizzi said, about "reading somewhere that artists have to deal exclusively with Wal*Mart, or not be sold there." Clearly that's not true...I have bought plenty of CDs there, as diverse as Miles Davis and The Dave Matthews Band. Obviously neither of those artists have an exclusive deal with Wal*Mart, but are sold there. But rumors like this get out there, and then people think poorly about the company, when it's just not true.
As far as the exclusive deals are concerned, it makes sense for some artists. Most music stores are targeted at younger audiences, and charge more while paying the artist very little, if anything at all, in royalties. While this may be ok for a Jonas Brothers, Miley Cyrus, or others who aim at the younger market, for classic rock stars, aiming at adults, it doesn't make sense to bend over backwards for these companies and get so little in return. It is estimated that as high as 75% of American adults go to Wal*Mart at least once a year, so it's not like you aren't putting you record where the people are. Because of their size, and because of making an exclusive deal, Wal*Mart is able to pay the artist more per copy sold, thus the artist profits more, Wal*Mart profits, so both parties are happy. For those who don't live near a Wal*Mart, they sell them online, and even with shipping, it's still cheaper than somewhere like an FYE, so in the end, everyone wins except for the retailer who is trying to rip the artist off.