That truck carries 500 packages. That drone one or two at best so to replace one truck you're looking at 100's of flights + return flights. And I'm not convinced the risks are lower.
A truck travels a greater distance to deliver those 500 packages to the same locations, as it must take roads instead of flying in a straight line. And roads are much more likely to have people on them than a random patch of ground. Also the truck weighs several tons. The weight requires more energy to move stuff around, and has more kinetic energy than an 80lb drone.
Trucks also don't sound like a swarm of angry bees, in fact the all-electric fleet that Amazon uses around here barely sounds like anything at all. Drones would be a huge step backwards for noise pollution.