This is why straight going traffic always has the right of way if the roads are similarly sized, and it's on the turning vehicle to stop and wait at the turn.
I would also hope that self driving cars are programmed to drive defensively and conservatively over trying to shave off a second or two of drive time.
California does not have the "Idaho Stop".
Drivers(Idaho included) by and far embrace the California Stop colloquialism if you ask me. The majority of traffic on roads is cars and the majority of traffic rolls through stop signs.
However I think that is irrelevant, depending on whether the description I heard is correct - it sounds like Waymo turned so quickly after a truck that it could not be certain its path would be clear. That to me seems like the real mistake.
But then that’s exactly why cars have stop signs. They trade high speed and carrying capacity against lethality.