At 200ft with low KV motors and big props they are nearly silent or at least quiet enough that they blend into the background. If you fly following surface streets you remove a lot of the "drone falling on someone possibility" and insurance can handle damage to cars if something were to go wrong. Keep in mind they can also be fitted with parachutes and airbags that can be deployed for safety.
Right now the biggest holdbacks are losing GPS lock (flyaways are not fun) sense and avoid (don't hit stuff) and battery life.
You can easily build a multicopter with current tech able to fly 5km+ and back in under 10min (I've done it) the issue is that due to the weight of the batteries you don't end up with much payload left to speak of. As better battery tech is rolled out and other stated problems are solved drone based logistics will be viable, I give it 5 maybe 10 years max and am very bullish on it.