There may indeed be more to the story.
I come from a rural background. Many people drive 80 kph (50 mph) on these roads. And they hit the ditch more often.
There might be some weight restrictions that prohibit big trucks on this road. The pavement in the photo (or oily gravel) looks a little on the weak side to me.
Anyways, we need more info to know why this thing has remained in the ditch for 67 years.