Except it won't work for heavy packages. And it won't work near airports. And it won't work in bad weather. And it's a safety risk to people on the ground. And some simpler answer will always be better. In 30-50 years, truck delivery and logistics will have made progress too.
Think about it. What real world conditions would have to exist for drone delivery to make more sense than trucks?
Traffic? Use two-wheeled vehicles instead of trucks.
No drivers? Driverless trucks or some other ground-based driverless vehicle.
Here's the one situation where airborne drone delivery may make sense: deliveries to boats, to the wilderness, or to people across a body of water with no bridge. That's it.
Or maybe in 200-400 years, when all the challenges to drone delivery have been rendered trivial, it will still be easier and cheaper to use trucks, but since all the problems are trivial and airborne drones are cooler and faster, maybe then use drones sometimes.