If I buy a smartphone on amazon, guess what they try to sell to me next? I'm constantly disappointed by tech giants ability to do their job: selling things to m

If I buy a smartphone on amazon, guess what they try to sell to me next? I'm constantly disappointed by tech giants ability to do their job: selling things to me. They don't even need these fancy machine intelligence stuff. A "switch case" could make bettere recomendations than the state of the art. But the highlight in recomentdation business is still: buyers who bought x also looked into y.