Why would the per hour cost of the drone be higher than even a minimum wage worker?
The drone can work more than one shift.
The drone doesn't take vacations.
The drone doesn't waste time chatting with co-workers.
The drone is out there.
The drone can't be bargained with.
The drone can't be reasoned with.
The drone doesn't feel pity, or remorse, or fear.
And the drone absolutely will not stop, ever, until the parcel is delivered!