Those drones are not supposed to get close to the ground at any time.
People picture the thing swooping down and landing on the front walk..lol
With dogs and kids playing in the yard there would soon be fur and blood flying... and huge lawsuits emerging.
They are to let the package down on a cord and release it from the end....staying well away from the ground. If by some chance the ground does get too close the engines halt immediately and the rotors freeze. Also some sort of near-instant inflatable safety device will deploy to soften the falling gizmo... a drone air-bag of sorts.
It’s all still a few years off anyway.