I agree. When we have self-driving cars, why would a drone be cheaper then having a self-driving truck drive around and drop stuff off? Also, I don't see a drone bridging the last step to your doorstep. What if it's a large package such as an air conditioner? There's so many odd package shapes and sizes. Why not just a robot picking up the package and walking it to the door? Then you could sign for packages as well.