The current dealership model creates and tolerates incentives for dealers to rip me off at sale time. It also injects a set of complexity into the model, where if I choose to buy a car of brand X, I then have to comparison shop for the exact same car at multiple dealerships.
I've bought two Teslas, and the nice thing about the process is that it doesn't matter where I pick up the car, I get the same price, and the exact same experience. Tesla also won't try to rip me off on buy-ups like tire protection and seat protection. (Then again, Tesla really needs price protection because they significantly dropped the price of the Model Y shortly after I bought it.)
One of the most annoying situations was a Subaru dealer that made me sit through a pitch for various upsells (that were rip offs) and then sign a form that I listened to them.
I really hope the Amazon car purchases explicitly prohibit upsells and other nonsense. Just bring me the car, give me the keys, and stay long enough to make sure that the car works. No BS upsells.