Well, that's why they want the robots! If your robots are capable enough, and if your AIs are smart enough, why, they could just build the yachts directly!
Right now, ordinary humans are needed by the economy because we do all the work, and because robotics hardware is still far behind AI. But there's no inherent logical reason why you need a human to turn raw materials into luxury products. The really important questions are: Who controls the AI and robots? How good will they get? Who or what does all the work? And who controls the natural resources?
> Of course (let me go distopic)
Yup, that is a possible end state.