"costs more than a truck with a driver". Are you sure? Where is your math? Amazon will have a central "flight center", technical schools will start offering single semester "drone flight" classes for 2 and 3 year pilot programs; possibly an entire degree program including maintenance and repair.. Here in Tulsa we have Spartan (yes, the same school the 9/11 guys trained at lol)...Amazon could easily set up a flight center on the airport property and hire students on shift work, interns, hire graduates, etc. We already have tons of call centers here; the city of Jenks would JUMP at the opportunity to pull something like that here. It would be a win-win for all.
Eventually the "big boys" will jump on this too. I work doing ITSM for AA / USAIR / etc, there's little stopping integrating drones into M&E and all the other backend systems. Well, other than the FAA moving at a snails pace.