goldenlaw, interesting thought but, (1) I don't think anything on the $4 list is being sold under cost & (2) In today's environment I dont't believe WMT could damage WAG significantly with a price war.
For some generics, $4 is less than cost. I think Walmart has determined that this is the only way it can drive a Walgreens out of the competitive field. It was easy enough to beat the tar out of other specialty retailers because they were not that good at what they do. Walgreens is very good at what it does. As such, Walmart is playing dirty and looking very long term on this front. As a WAG shareholder, I sure hope you are right.