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

From Why Wal-Mart Will Never Pay Like Costco by Megan McArdle.

In other words, Trader Joe’s and Costco are the specialty grocer and warehouse club for an affluent, educated college demographic. They woo this crowd with a stripped-down array of high quality stock-keeping units, and high-quality customer service. The high wages produce the high levels of customer service, and the small number of products are what allow them to pay the high wages. Fewer products to handle (and restock) lowers the labor intensity of your operation. In the case of Trader Joe’s, it also dramatically decreases the amount of space you need for your supermarket ... which in turn is why their revenue per square foot is so high. (Costco solves this problem by leaving the stuff on pallets, so that you can be your own stockboy).

Both these strategies work in part because very few people expect to do all their shopping at Trader Joe’s, and no one expects to do all their shopping at Costco. They don’t need to be comprehensive. Supermarkets, and Wal-Mart, have to devote a lot of shelf space, and labor, to products that don’t turn over that often.

Wal-Mart’s customers expect a very broad array of goods, because they’re a department store, not a specialty retailer; lots of people rely on Wal-Mart for their regular weekly shopping. The retailer has tried to cut the number of SKUs it carries, but ended up having to put them back, because it cost them in complaints, and sales. That means more labor, and lower profits per square foot. It also means that when you ask a clerk where something is, he’s likely to have no idea, because no person could master 108,000 SKUs. Even if Wal-Mart did pay a higher wage, you wouldn’t get the kind of easy, effortless service that you do at Trader Joe’s because the business models are just too different. If your business model inherently requires a lot of low-skill labor, efficiency wages don’t necessarily make financial sense.

That’s not the only reason that the Trader Joe’s/Costco model wouldn’t work for Wal-Mart. For one thing, it’s no accident that the high-wage favorites cited by activists tend to serve the affluent; lower income households can’t afford to pay extra for top-notch service. If it really matters to you whether you pay 50 cents a loaf less for generic bread, you’re not going to go to the specialty store where the organic produce is super-cheap and the clerk gave a cookie to your kid. Every time I write about Wal-Mart (or McDonald's, or [insert store here]), several people will e-mail, or tweet, or come into the comments to say they’d be happy to pay 25 percent more for their Big Mac or their Wal-Mart goods if it means that the workers are well paid. I have taken to asking them how often they go to Wal-Mart or McDonald's. So far, no one has reported going as often as once a week; the modal answer is a sudden disappearance from the conversation. If I had to guess, I’d estimate that most of the people making such statements go to Wal-Mart or McDonald's only on road trips.

However, there are people for whom the McDonald's Dollar Menu is a bit of a splurge, and Wal-Mart’s prices mean an extra pair of shoes for the kids. Those people might theoretically favor high wages, but they do not act on those beliefs -- just witness last Thanksgiving’s union action against Wal-Mart, which featured indifferent crowds streaming past a handful of activists, most of whom did not actually work for Wal-Mart.

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.”