Just as there is product-market fit, there is also product-company fit. Amazon as a company has their own cost of capital, earnings expectations, talent distribution, and organizational capacity. It is not a place where the best of the best work in mainline product development, nor is it a place that is willing or able to go through long periods of losing money in order to rapidly improve the product. The Amazon of old did that, and had different capabilities, but today's Amazon is not the same company.

Notice that you also see Google really struggling (and falling behind) in the AI race. This, despite massive resources and being responsible for key pioneering research. Same reason why IBM has failed in this area. The big established companies tend to shut their brightest people into research departments where they write papers and produce demos while the main cash cow areas remain undisturbed, so they have collections of bright people and they have money, but they rarely let their brightest people make big bets with the money, whereas startups do.

It's also why poor people spend more on lottery tickets than rich people.