Humans are inefficient and unsafe machines, to be sure. Soft and fragile, slow to respond, 98% blind to the EM spectrum, insanely low communication bandwidth, unusually difficult to motivate, prone to acts of defiance, uncalibrated and wandering accelerometers and rotation sensors, very low precision parts, require a host of special atmospheric and environmental conditions to be met, etc.

We're replacing them as fast as we can, honest.