>with only minimal requirements made of the driver.

could easily be changed by changing the requirements.

Commercial drivers are involved in collisions less frequently, and the more stringent licensing requirements (i.e. a law) are probably helping with that.

Drivers knowing that they will get away with mowing down a pedestrian so long as they say they didn't see them is also going to encourage dangerous driving.

Most importantly, laws that promote safer street designs make a massive difference in pedestrian fatalities.

All this to say that: laws do protect people from 2ton hunks of steel.

This is silly. Nobody thinks this. ”Mowing down a pedestrian”, even if one has a perfect legal defense, would be incredibly traumatic even for the driver. Traffic rules ought to be engineered with practicality (physics, the limits of human cognition and visual perception, etc.) paramount.