While it is hard, impossible is a stretch. You can buy drones with autopilot that will land at a point as long as you have 10 ft of clear space. A friend yesterday was using one he'd received for $3000 to film some cliff tops while we were walking the edge. After shutting off the remote it can fly back to where it was turned on so you don't have to carry it. Bear in mind this is with tech that's a few years old.
Yes, as long as there isn't a crane, net, tilted lamppost, kite, human, dog, or any other unplanned obstacle.
Come on, people. Being able to draw a trajectory isn't the same as moving a physical object through space. And moving a drone to a predetermined GPS location in ideal conditions while you are watching it and when you know there is nothing around has nothing to do with day-to-day deliveries using drones.
So you believe sensor based obstacle avoidance is an impossible problem in robotics? Second, unrelated question, do you think drones need to complete 100% of their scheduled tasks or do you think it's acceptable to fail a small fraction of the time?
I know, but with the Raspberry Pi's and similar tech we can't be that far away from something that's technically feasible. We also don't know what Amazon has been working on behind closed doors. They are known for vast technical prowess after all.