Professor Steven Landsburg of the University of Rochester:

Writing in Slate:

All of which is pure speculation, and pure speculation can lead one badly astray. My colleagues and I have a little game we sometimes play at lunch. We pick a local business and estimate its profit. (How many customers do we see going in per hour? How much does the average customer spend? How many employees are there, and how much do they probably earn? And so forth.) Our conclusion has invariably been that the business in question is losing money fast enough to bankrupt anyone this side of Bill Gates. Yet after 20 years, most of those businesses are still there. The conclusion is that either most retail establishments are owned by eccentric billionaires, or there's something about retailing we haven't figured out.

He's got a book too, Armchair Economist: the Economics of Everyday Life (and other books).