I dont think that in increase in commercial drone usage for package delivery would cause more congested recreational airspace. Amazons altitudes for its drones would be around 800 - 1000' agl, so wont interfere with recreational flights.
I dont think that drones would cause a hazard to grandmas or dogs if they are landed at the Amazon type locker centers. I wonder how many injuries and fatalities are caused by UPS, USPS and Fedex vehicles every year? Those vehicles clog the roads, create emissions nightmares, and depend on the whim of the weather to get your package to you. Drones will have no such limitations, even in strong winds.
In my Amazon example, you would never even see the drone that just delivered your package. Yes someone in a cubicle would be commanding the launch by a ground station at Amazons distribution HQ or from really anywhere in the world, and that same person would be commanding and tracking dozens of drones during the day. Same as ATC do now, but they wont have to give verbal instructions to the drones, as ATC's do to ATP's. I have been wondering for many years why ATC has not been digitized to give digtally transmitted vectors to aircraft instead of a verbal ATC, who could give the wrong verbal command, or just be having a bad day.
The US military has been using autonomous drones successfully for many years, and all that technology that the military uses eventually trickles down to the consumer market. Aircraft have jetways, drones could have droneways. Even on the Jetsons cartoon, their space vehicles stayed to the right and had designated jetways. A carton could be reality in the not too distant future.