This only captures crashes with other road users. Increased speed increases a lot of other risks, such as risk of injury to pedestrians at crosswalks or sidewalks, increased risk to hitting a building, and of course the general depressing effect that happens on non-car usage of roads (how many people will want to ride a bike on a road where all car drivers are speeding?).

(This is one of my big issues with US speed limits. All the discussion around it is always scoped only to other cars for the most part.)