I’d love to agree with you, but unfortunately as humans we are not infallible. We cannot rely on people to look in every direction and see every hazard constantly. The driver may have been distracted, for example by sun strike, and the pedestrian may have not seen the car due to its colour.

Roads need to be designed for their purpose, and their purpose also includes allowing pedestrians to cross safely even if the pedestrian and the driver suffer from a momentary distraction.