Yeah, I suspect the core motivation is to combat paradox of choice. Doing so is in the best interest of both the customer and Amazon.
Amazon's choice arrived years after my tenure at the big A, and I'm not sure it's directly connected, but it definitely helps solve this problem.
If I told a personal assistant "I want any kettle", they would know there's an implied <among buy-it-for-life high-quality stainless steel in America with a non-garish finish>.
They would also know me well enough to provide options when it's a non-commodity context, ie pressure cookers where the same implied values hold but I want to actually made the feature tradeoffs as a poweruser.
YouTube went down then global optimization path, and the experience was terrible...