"The lidar in question should easily have seen a person walking a bicycle in the middle of the road. There was some failure that wasn't caused by the lidar manufacturer's "not enough lidars" excuse. "
You are assuming that the approaching human in question was in the 'cone of surveillance' for the lidar. With the reduction in sensors, that zone may have been relegated to another type of sensor, leaving the lidar for long range detection in the vehicle's planned path.
In that case the human would be invisible to the lidar until stepping in front of the car. Take a few fractions of a second to analyze and recognize, and you've run out of time.