When a company as great as WalMart emerges on the scene, the other players in the industry have got to be on their A game to compete. WalMart has driven many stores out of business, because they offered the superior choice to the consumer.
If WalMart actually uses it's superior positioning to offer products at a *loss* to consumers, they can only maintain that pricing for a finite period of time. They might drive a competitor out of business, but they'll eventually have to raise their prices to continue operations. That gives someone else an opportunity to compete again, and in the meantime the consumers haven't suffered one bit. The other business that couldn't compete has suffered, but that's the risk you take when you engage in fair competition. Some people win, other people lose, but society always benefits. Attempting to rig a system where nobody loses always leads to everybody losing over the long haul.
Now imagine if the regulatory and tax burden were less. WalMart's competitors might be able to afford a stronger response to WalMart's consistently low prices. All that time, energy and money spent paying off the government would instead be channeled into providing better quality products at lower prices for the consumer, because refusal to engage WalMart in honest competition would spell demise.
Ultimately, wherever WalMart has engaged their competitors in tough competition, the consumer has benefited enormously.
A very good analogy exists in the technology sector: Back in the 90's everyone and their grandma used Netscape as their internet browser. It was superior to anything else on the market, and you could have your own fully functional copy for a meager $30. Microsoft was floundering on the web, and so they offered their competing browser Internet Explorer for *free.* They spent millions on development, advertising and distribution, but they never charged their customers a single cent.
Arguably, Internet Explorer was an inferior product to Netscape, but it didn't mater. Why spend $30 on something when you could get a competitor's product for free? Microsoft used its massive financial resources to drive Netscape out of business and establish themselves as the dominant browser company. Netscape lost, Microsoft won, but what did the consumers get? Free browsers.
Flash forward more than a decade later and browsers are *still* free, to this day. The companies who produce them found other means to raise revenue, by bundling products, engaging in targeted advertising, and promoting their search engines. Consumers today couldn't ever imagine *buying* a web browser, and competition is more robust in that sector than *ever*.
What happened? Microsoft, drunk with victory, got lax in keeping Internet Explorer up-to-date technologically, and began offering a poorer quality product. New competitors emerged. First it was Opera, then it was Mozilla Firefox (an offshoot of what used to be NetScape), and then Google offered up Chrome. Microsoft was unable to maintain its aggressive position in the market, unable to choke out all of their competitors, and now Internet Explorer is struggling to reattract users after having lost them. But the end result was a massive win for the consumer. The web browsers today kick ass, and we don't pay cent for them, all because the *evil* Microsoft engaged in *unfair* competition.
Oh, and by the way, WalMart still faces stiff competition from Fred Meyer, Target, and other national chain stores. We're nowhere near seeing a monopoly.