Another factor could be weather conditions. Heavy rain/snow/wind could all affect range or even accuracy (heavy precip can interfere with GPS to some degree). Drones also probably work better in a suburban environ, but less in a dense urban area or less dense rural area. Also, maps can be terribly slow to update. My home is in a Chicago suburb, about 8 years old now. Google maps still cannot accurately plot my address. Personally, I dont look forward to "we dropped off your package where we think your address is" and yet the package is a few hundred yards away. I'm also reminded of one of my favorite fuckups, this by USPS: my Mom misquote "street" instead of "drive" on my address, street number, name, city, state and zip otherwise being correct, and the overnight package landed in Florida instead of Illinois...
Legality: how high above your property do you own? Would a drone flying at 50 feet be trespassing? 100? 200?
Loss: how do you recover a crashed drone? Or one intentionally downed?
Range: how much power can you pack onboard without compromising payload capacity?
Payload capacity: how much can you reasonably lift?
Cost: dollar for dollar, is it more cost effective than trucks (even robotic ones)?
And so on.