One possible answer would be that we aren't intelligent enough to create such systems. I don't think that's true but its a possibility.

> we aren't intelligent enough to create such systems

Evolution suggests that you can, in fact, create systems that are more intelligent than what came before them.

Evolution achieves that in part by a callous disregard for individual lives. The intelligences that evolution has produced are built on an unimaginable pile of corpses. Even Uber doesn't seem quite as willing as mother nature to spend quite so many lives to achieve incremental improvements.