Megan McArdle, (not my favorite writer mostly because she overestimates her own intelligence) has a very strong article at bloomberg.
If you want Wal-Mart to have a labor force like Trader Joe’s and Costco, you probably want them to have a business model like Trader Joe’s and Costco — which is to say that you want them to have a customer demographic like Trader Joe’s and Costco. Obviously if you belong to that demographic — which is to say, if you’re a policy analyst, or a magazine writer — then this sounds like a splendid idea. To Wal-Mart’s actual customer base, however, it might sound like “take your business somewhere else.”
Target demographics matter to business models just not to those who never started a business or are too dull to think.