>17747742
changing the shelf tags requires labor which costs money. they just don't change the prices of everything when the input costs change.
you can make any argument that you like. they don't do that.
track the prices of things by looking at the weekly flyer at the supermarket week in, week out. sometimes split chicken breasts are on sale for .99 a pound. other times, 2.49, prices do not match the costs.