Thousands, maybe even millions of businesses have been taken down by Walmart. Many people have been broke or made rich around the world by Walmart. Is this unique or is it the way it has always been?

I'm unsure how long the idea of a modern 'company' has existed. But the East India Company had control of several countries/colonies in its time. And before that I'm sure there were very influential merchants - probably those favoured by the monarchy. Trading and politics and government have always been interlinked, but perhaps control has shifted over time from the government to the corporations.

Modern technology does help when a large corporation wants to coordinate things on a global level, of course.

http://www.businessweek.com/magazine/content/03_40/art03_40/0340pe_walmart.jpg