Western airliners are very safe, but the USA averages one GA accident per day:
https://www.faa.gov/news/fact_sheets/news_story.cfm?newsId=2...
Helicopters have much worse failure modes, even in multi-million dollar aircraft. Small drones are the worst of all, and should not be flown over populated areas.
https://en.wikipedia.org/wiki/Jesus_nut
The FAA historically has regulated that aircraft fly 500' and above over non sparsely-populated areas for a reason. Or you lose your license.
Drone deliveries fundamentally violate that, as regardless of where your warehouse is located, you're deliberately flying towards a populated area (ie. customers.)
The above is why the FAA has justly been slow on allowing drones into the airspace, and why you have to register them.
A constructive comment I can add is that I can only see delivery drones being safe with a built-in fixed wing that allows it to glide to the ground power-off below 10 mph.
Source: commercially-rated airplane pilot.