However, Waymo is Deep Blue of self-driving cars. Doing very well in a closed space. As a result of this geofencing, they have effectively exhausted their search space, hence they work well as a consequence of lack of surprises.
AI works well when search space is limited, but General AI in any category needs to handle a vastly larger search space, and they fall flat.
At the end of the day, AI is informed search. They get inputs, and generate a suitable output as deemed by their trainers.
In other words, since they accept liability for their cars it's not in their interest to roll out the service too fast. It makes more sense to do it slow and steady.
It's not really a strong argument that their technology is incapable of working in general areas.