I guess I worded it incorrectly. My point was that it's two completely different ways of selling you things. Supermarkets use all these techniques to subconsciously make you buy more things, but they rarely try to sell you a singular product.

Product websites actively try to distinguish themselves, to make you feel that the product is unique and convince you it'll make your life better. Having the same style of website for every product ever feels like something that'd actively go against the goal of the website. After all, if two things look the same, why would I pick one over the other?