This strikes me as similar to the common explanation of why Whole Foods "appears" so expensive when apples-apples comparisons can show prices there to be similar to those of Safeway; yes, the apples cost the same, but Whole Foods gives way more prominence to the super-expensive rare varietal organic local apples that cost 3x as much.

Net result: whatever the absolute price comparisons say, it takes more mental effort to shop cost effectively at Whole Foods.