Wal-Mart does pretty much everything well, or at least according to plan. So the news it's backing off the expansion of in-store medical clinics offers up a rare Wal-Mart failure.

Wal-Mart had planned to open 400 clinics by next year, but as of February had just 31, and that's down from 78 the year before, according to Business Week Magazine.

When in-store clinics started popping up some years ago, it seemed like a genius idea, for both patients and the retailer. As a person who works for herself and occasionally gets sick, I am one of those casting about for a place to get quality treatment for a reasonable fee.

Several month ago, suffering from a back injury and crappy insurance with a really high deductible, I stumbled into a clinic at the local Walgreen's looking for some kind of relief. I found a sympathetic nurse practitioner who prescribed what she could, found me a specialist, made the appointment and called me at home to follow up. All for less than $60, plus the drugs. In the end, I saw two more doctors and met my high deductible in physical therapy, but the clinic was a good starting point for me, and the practitioner a lot more attentive than many doctors.

Are these clinics profitable? Not many, according to some. And Wal-Mart's inability to make it work raises serious questions about any retailer being able to do this profitably.

Wal-Mart's clinics are run by third party operators that rent space from the retailer. Drug chains typically form a partnership with their providers, making a more solid foundation with shared resources available to weather dips in business.. Nevertheless, several have already declared bankruptcy and gone out of business. Profitability, it seems, requires critical mass. But with more of us out of work every day and health insurance increasingly beyond reach, Wal-Mart's ability to lower costs and leverage efficiency could really come in handy here.