Amazon Prime Air's drones are plagued with practical problems that would make them inviable in urban environments for the foreseeable future. What about Amazon Rockets? They're only a bit more ludicrous.
But seriously now, what Jeff Bezos should really do is build a delivery network made of supersonic pneumatic tubes connected to every home in the United States. Using Elon Musk's Hyperloop technology, of course. This idea is just as viable as his drone project.