Why do you think that Amazon would be less likely to use a distributor than stop and shop, Walmart, target, or Costco?
I don't think wal-mart and Costco use a distributor.
Walmart definitely does for some items. I didn't think Costco does, though
I've done a lot of research on the food supply business as it relates to chametz. Everyone buys from distributors. They also buy from food brokers, and Costco also buys from closeout brokers. It's unusual for anyone to buy from manufacturers directly. There is absolutely no way to know who owned a specific item on pesach, there is just more of a chashash right after pesach in a store owned by a Jew. (and that persists to some degree year round, X days is very arbitrary, based on what we know of how stores rotate stock etc.)
But very difficult to assume that any specific box of macaroni was owned by C&S on pesach. (and C&S is not owned by a Jew for Pesach).
However I understood OP's question to be referring to FBA items where it's stored by Amazon and shipped by them but not necessarily sold by them. Looking back, I misread. Shipped and sold by Amazon is the same as any public company, see zecher Yitzchak 8.