Long story short, It's the FAA's fault. Initially they said, "no, you can't do that" because there are no regulations for that. With pressure from companies, the FAA took years to create the rules to make drone deliveries legal. Finally there is some regulatory framework. Drones have to be specifically designed and manufactured to pass the FAA's certification program. We've all seen capable drones from Amazon's marke…
Good. Without their careful and considered work, the US skies would experience it's own tragedy of the commons. There's a reason air travel is so damn safe, and it's not because private companies were left to their own devices.
"The Air Commerce Act of May 20, 1926, is the cornerstone of the U.S. federal government's regulation of civil aviation. This landmark legislation was passed at the urging of the aviation industry, whose leaders believed the airplane could not reach its full commercial potential without federal action to improve and maintain safety standards. "
Maybe people were smarter in the '20s, maybe they were hoping for regulatory capture? Not sure, but obviously it's a good thing...
https://en.m.wikipedia.org/wiki/Federal_Aviation_Administrat...