the difference is that grocery stores are easy to search completely - don't like the cereal options on the end-cap? just walk down the cereal aisle and see it all immediately.
Amazon on the other hand, actively makes it difficult to search for other products, by not only promoting their own brands at the top, but filling up the rest of the results with sponsored items.
It's more akin to an endcap with highest bidder items, but then every few feet you walk down the cereal aisle, the shelves separate and move farther away so another endcap can slide into view, pushing the cheaper alternatives farther and farther down the aisle the further you walk.
Not to mention the scale of the problem as well, grocery stores are finite, and amazon nearly infinite, at least in terms of how much time it takes to search through everything.
Amazon on the other hand, actively makes it difficult to search for other products, by not only promoting their own brands at the top, but filling up the rest of the results with sponsored items.
It's more akin to an endcap with highest bidder items, but then every few feet you walk down the cereal aisle, the shelves separate and move farther away so another endcap can slide into view, pushing the cheaper alternatives farther and farther down the aisle the further you walk.
Not to mention the scale of the problem as well, grocery stores are finite, and amazon nearly infinite, at least in terms of how much time it takes to search through everything.