I think most trades would be better served by a van rather than a pickup truck. Ingress and egress is much easier. It is also easier to load and drive due to lower center of gravity. Expensive tools are out of the elements and generally safer (and so less risk of tools and material making their way onto the highway). Plus, better drag coefficient and so better efficiency. Finally, a roof rack allows for those items you mentioned like sheetrock and plywood, ladders and pipes.
The biggest problem I see is most of these men have an ego that would never allow them to buy and drive a van.