I always assumed that drone delivery was just a publicity stunt (in urban areas anyway). I am hoping that it stays that way. I am really not convinced that a sky full of buzzing drones delivering people's toothpaste and takeaways is a great idea.
Only if you don't price in all the externalities: loss of delivery jobs, environmental cost of the drones, cost of drones hitting people, cars, buildings and powerlines etc.
Like if you switch from a low quality butcher to a higher quality butcher, you are not imposing a cost on the lower quality butcher.
You can not like it as a consequence of course, whether it is an externality or not.
Replacing 3 delivery guys with 1 drone maintenance guy imposes a cost on society if those delivery guys can't then find work.