The short answer is money. The long answer is those companies lobbied hard to be them to decide who gets treatment or not.

Engineers want you to pay attention to the road, the most useful trick they have, is follow the terrain topography. Unfortunately, the topography doesn't always work with you, because the straighter the road is the more boring and fatiguing it becomes, so much so, Australia has fatigue zones in some highways where to keep you awake and alert, there's trivia questions every few miles.

Their heads work like a gymbal for cameras completely isolating their heads of any movement when walking.