It's interesting that you chose a competitive market to compare this with. In a competitive market, efficiencies go to the customer. In an oligopoly or monopoly, efficiencies go to the provider.

It's obvious that baking your own bread is a bad idea if you're okay with what you can buy from the competitive market. It's equally obvious that baking specialty, artisanal bread (and buying the commodity ingredients, such as flour, salt, and yeast) is cheaper than going around to several grocery stores to try to find the exact kind of loaf you want.

AWS is in an oligopoly, so it should be obvious that its efficiencies (in this case, its economies of scale) are not passed on to the customer. The strong, clearly expressed claim was fine.