Blame manufacturers willing to drive themselves out of business because they can't say no to Walmart. Wally-world often tries to bully manufactures into selling product to Walmart at little to no profit, and when a manufacture isn't willing to put their company out of business for such a ridiculous demand, Walmart finds a manufacture who will. After that manufacture drives themselves out of business, Walmart finds it's next victim/sucker.
The best example is Vlasic pickles, Walmart was selling a 12lbs jar of pickles for 2.97, a 0.03 profit for Vlasic, sure that might be about 370,000 a year depending on volume of sales, but who can run their business at a 1% profit? Walmart did its homework, Vlasic did not and Vlasic paid the price, dumb asses.
Is it Wallmarts fault, I say no. Its manufactures faults, and now since the dumb ones have put themselves out of business, or became wise of the situation and decided not to buckle to the demands of wally-world, wally-world is forced to market some off-brand or raise prices.
For awhile, Walmart didn't post a profit for several months, and if you noticed prices have gone up across the board. Walmart was even busted for raising toy prices near Christmas time for the last couple of years. You were able to get a much better price at different retailers, but since people were already at Walmart they purchased it there without checking prices.