Do you have any data that isn't subjective? I have subjective data saying the opposite.
8/9 times when I shop Around Amazon has the best price. If it's close, like a buck or so difference, I still choose Amazon due to reliability, speed, and me having a history of good customer service interactions.
I buy everything I need every month on Subscribe & Save (from tooth, toilet paper, to batteries, air freshener, etc) and the even greater 15% discounts add up as well.