That's exactly how amazon decides what becomes an amazon basics product.

AWS has also strip mined open-source software, elasticsearch, redis, mongo, browser rendering tools, etc.

Given that even non-Amazon vendors can use Amazon.com search features to discover bestselling products from third-party sellers in various categories, I doubt there's anything contractually prohibiting Amazon from using the same information to drive their own product mix.

Same goes for selling prices. Published retail prices are not trade secrets.