The truth is that many core components used in drones are an inheritance from the model airplanes industry. The engines of drones may be dazzling, but they can't even tickle car engines let alone aircraft engines. Keeping people in motion safe for decades now vs. carrying “petty” payloads for some years is probably the root cause.
It is not a real match when you compare a drone to a car. The amount of knowledge, ingenuity gathered to improve and resources invested in the car industry is overwhelming. And yet this is a fascinating comparison as the development of UAVs is sometimes dizzying.

This is why the development of a drone hardware setup is a combination of fine engineering and art. A continuous journey to integrate the best available core components and extract their capabilities to the top.
Drones are not as foolproof and well-founded as cars; the path is still long – but we are getting there.