Why does Amazon buy cardboard?

Amazon must be a huge consumer of kraft cardboard. We have a model in which product is shipped in cardboard and then, in most communities, is picked up at the curb for recycling. Why don’t we turn this around?

Why aren’t the deliveries made in something akin to a mailbox, but for packages. With limited packaging (ie, soft packaging, reusable totes, etc) and then we have curbside or community drop off of goods? 

Today the brick and mortar retail world relies on customers picking up goods from a store and trashing the packaging at home. What if it was the opposite? The goods were delivered to the home and we dropped off the packaging (on our own schedule). As tools like Amazon become more ubiquitous, the infrastructure for curbside reusable pick-up is a natural next step.