probably because they can control the market and offer lower prices in the short term and when they become monopoly they can jack up the prices.And why do you suppose big business kills small business? I'll answer for you - because they offer more at better prices. Simple and plain. Small businesses need to find a niche or location they can thrive. It's the reason you don't do all your groceries at the corner convenience store vs the large grocery store. I'll cost twice as much to eat. It's there to get something quickly so they stay in business for that convenience.
i avoid walmart. but i shop at superstore. its union at least but far from perfect. id prefer if all the workers owned it.