I don’t intend for this to sound judgmental, and I may be mistaken, but I don’t think Walmart customers were ever exactly the most music-loving people around. Or perhaps it is that they, like myself, are just not interested in the music that is currently most popular.
In the retail business, product has to "earn" its’ space on the sales floor. The amount of income generated by every square foot of floor space is analyzed every month or quarter; the product that does not generate the amount of income needed to meet the requirements of the "formula" has its’ floor space reduced until those requirements ARE met.
Music is just not earning its’ keep in Walmart. My two sisters are Walmart customers (I had never been in one until a year ago), and neither would think of buying a CD, or for that matter sitting and listening to an entire album. The people who ARE buying music aren’t doing it at Walmart, and haven’t for a long time.