You missed one. A big one.

Cost.

People will drive an extra 5 miles to save $0.50. look at a company like Wal-Mart. Customer service? Half the staff isn't old enough to vote at a typical Wal-Mart, you don't get quality customer service from a place like that.
What you get is a great price (or the perception of a great price, wal-mart is frequently not the best price around and their products are often poor quality which means you'll have to come back again sooner for a replacement).
Considering that they are likely the single largest corporation on the planet, it's no surprise that cheap products with low customer service is a common, and highly profitable, business model.