[Big Dave]

As you can see there has been a lot of work done. Some guys work quite hard on their tractors.

What defeats these efforts is the "disposable" nature of the trailer. A truck often takes a trailer to a dock and drops it off and goes out into the yard to pick up another going elsewhere. He/she has no investment in the first trailer so why worry about it.

Also, a lot of what look like van-type trailers are actually containers on modified flat beds. In order to maximize the number of containers on the ships, the containers maintain a very regualr and flat silhouette.

Thanks to sheer volume, Wally-World can dictate. Nobody else can.