Pickup trucks aren't flat vertical walls like a semi though. They are a high wall with a hood.

While "sharp" edge can certainly break bones, getting hit with a high hood causes people to slam their head into the hood with very little travel time compared to a low hood. Head injuries are far more likely to cause death.

Of course, the risk varies based on height. Sharp edges a couple feet off the ground are far more dangerous to someone only a couple feet tall.