When you order something, do you express where you want it sent in coordinates or as an address? You can't assume that the device's coordinates at the time the order is made correspond to where the order is supposed to be sent, even if the device gives coordinates. Plus, they're either not precise enough (could encompass the yard of the house next door, or just the snowbank at the edge of the property) or too precise ("drop this in the center of the roof because that's where the coordinates are"). You'd need software capable of parsing building layouts well enough to figure out where the main entryway is and leave the parcel there, or you'd have to require that people interested in receiving deliveries by drone put a beacon where they want the drone to drop stuff.

Beacons are the simplest solution, but they immediately put Amazon in a position where most people won't care enough to set them up.

eventually

It's been ten fucking years. They are one of the top five companies in the world. What are we waiting for here?

All of the investors that originally paid into the idea have already made their money. There is no reason to continue the project.

Can you point to deliveries that actually use any of that?