I might be off base, here, but I wonder if this is even remotely ethical.
(Yeah, yeah, what do you expect from Wal*Mart, etc.)
Even a not-terribly tech-savvy consumer (like, say, myself) can easily tell that these are woefully out of date and overpriced. I can't see how anyone capable of 15 seconds of online research could miss that, either. In my personal experience, "mere" poverty or lack of fancy schooling is not a barrier to knowing what's currently available. This really only seems to leave the possibility that these items are being maliciously sold to people who are unable to "defend" themselves: the very elderly, developmentally disabled, geographically isolated, and so on.
I don't for a second believe -- as suggested in the linked article -- that this is an innocent management error. Inventory is the store killer. Cash flow trapped in stagnant inventory will drag a business down, and any manager or accountant with a pulse will see this problem within a window of about a month, let alone a freakin' decade. Wal*Mart has a grip of accountants, and if virtually everything ever written about the company is to be believed, they are brutally efficient. Any product that didn't move at 1/2 off within x time would be sold at or below cost, just to get it out the door and off the books. The only logical reason that these ancient pieces of gear are still for sale is that they are selling.
Given all the above, and @Nadreck's assertion that this junk might not even work, I can't see how those sales are anything but baldly predatory.