Trust means something fairly specific legally. A group of businesses that team up to, in theory, monopolize a market is a trust. A cartel would be when those businesses are all the manufacturers or suppliers, leaving, for instance, retailers with no other recourse but to pay the higher prices that the cartel sets.
I think what you're thinking of with Amazon is more of a monopoly. I'm not sure they really need to team up with other businesses.
EDIT: Yes. I know that Amazon does not fit the legal definition of "monopoly". I was only saying that if we bend the legal definition of "monopoly" a bit in just the right manner, Amazon would fit. Whereas Amazon would never fit the legal definition of "cartel", or "trust".
They are certainly trying to vertically integrate all of their businesses. Prime video is hosted by AWS. Amazon is getting into the delivery business. Won't be surprised if Amazon buys a few cheap factories overseas after real estate crashes, or a container vessel.
I think what you're thinking of with Amazon is more of a monopoly. I'm not sure they really need to team up with other businesses.
EDIT: Yes. I know that Amazon does not fit the legal definition of "monopoly". I was only saying that if we bend the legal definition of "monopoly" a bit in just the right manner, Amazon would fit. Whereas Amazon would never fit the legal definition of "cartel", or "trust".