I heard about this earlier today as I was preparing and eating breakfast. Honestly, it sounds like a cool idea. It would be amazing to spot a drone carrying a rare, limited edition of *insert product here* as I longingly stare out the window.
From a more realistic perspective, I really do not see this happening so soon. There are probably many factors that go into this. The drones must meet safety precautions, as very little people desire a hunk of metal to crash into their newly refurbished kitchen. Plus, the government permissions necessary to run something like this is going to lengthen the process and potentially stop it all together. It is going to turn into a real issue if people go on online shopping sprees and their package ends up at the doorstep of a pawn shop.
Pricing is another issue. Thirty minutes is a lot fast than overnight shipping. Is it going to cost extra to get the service of these useful robots? Producing such machinery cannot be all that cheap. Between design, construction, programming, fueling, and, I would assume, many other parts that will go into the project, it should take quite the pretty penny to utilize. Not unless the drones for Amazon work in a similar fashion to the taxi business, though I have no knowledge on the business.
Overall, I think drones carrying products are going to be and interesting addition to society, but Amazon is going to have their work cut out for them.