The economics are definitely not there yet. The insurance alone would make it prohibitively expensive. Then you need a lot of infrastructure due to low range. Light drones also can't fly when it's too windy, too rainy, too cold. And they can only carry a very small subset of usual shipments (limited size and weight).
I see the drones as a last mile delivery solution. Rather than flying the drones all the way from the distribution centers to peoples' houses, they could drive their trucks out to your neighborhood, and then release a set of drones to deliver packages the 'last mile'. This would allow them to deliver a bunch of packages at once without the driver getting out of the truck, and larger packages could still be hand delivered for the time being.
Also, I'd imagine that the drones would be (remotely) human driven at least the first few times they drop off a package, so they can learn where to drop off the package (similar to how Google handles training their self driving cars). After that, they could drop it off automatically, but hand off control to a human if the environment looks too different.
I can imagine all the people complaining about how they have been waiting for three hours for an Amazon drone delivery while a hurricane rages on outside.
Those kind of drones are not the kind of drone that can deliver a package, unless that package can survive a ballistic delivery to the ground.
Sure, by shaping the drone into a winged vehicle you can get the payload capacity up and make it move quickly as it goes from waypoint to waypoint on a "delivery route", even in windy conditions. But now you can't deliver the package itself neatly onto the ground adjacent to obstacles like you could with a quadra-copter.
If someone can figure out a reusable payload delivery parachute or something like that with the ability to keep itself on course even in windy conditions to hit a drop point on the ground from a couple hundred feet up, and make it work with packaged goods the size of a small book or video game, then it has a chance.
Not sure what the deleted post is referencing, but Google is using a fixed-wing design. To deliver the package, you tilt the entire drone up to do VTOL. At this point you can lower the package. In theory, it will work and have higher efficiency than a multicopter design. I'm not sure whether or not Google has had any success with it.
