In short, Amazon shopping has become adversarial. Its website is premised on dark patterns. That's why its search sucks and prices and terms change on the fly. Look how noisy Amazon's web page is, how long the delays are, and how far down the page important discriminating information...like the product description...is buried. In particular, Prime is designed to confuse the value proposition. It mixes in differential pricing, video on demand, and shipping. A person can't look at it and determine how Amazon makes money off of Prime. Having had Prime, the obvious way it profits is algorithmically. It just shows me more products that are cheaper elsewhere.