> This just hit a building

Please be specific on what you mean by "just"? From the article:

> Amazon told CBS Texas that it’s investigating the cause of the crash that happened Wednesday afternoon.

Did it hit a bird? Did the wind blow something into it? Was it a 0.01% occurrence of some hardware failure? Who knows. Design flaw?

Extrapolating a few crashes within this new tech use case to a some fundamental flaw of drone flight isn't reasonable, at the moment.

I suppose a safe alternative would be pneumatic tubes dug to everyone's door. But, only things that are economically feasible can exist in the world. So, instead of perfection, we're left with the iteration and compromise that is engineering, regulations and enforcement to bound it, and insurance to catch the edge cases.

A large part of the FAA regulation around drones is one based on existing in reality, and it's lack of perfection, which is how much damage they can do (this is what limits the weight and speed).