Previous truck was to haul a race car on a trailer. Same fringe benefits for the camping shit, plus tools and spare parts for the race car (engines sometimes, wheels/tires, etc).
My electricians have pipe racks on their work vans, but if they’re buying 5,000 feet of 3/4” conduit (10’ sticks), you better believe a box truck will deliver it. If they need 40 feet for a quick service call, that’s what the pipe racks are for.
I agree with you though, the ability to move sheet goods flat in a truck bed is almost completely unnecessary.
If you really want to do this in a 5’ bed pickup, you can get a rack for above the cab and a crossbar with two posts that installs into the topper mounting holes near the tailgate to provide a 4’x8’ plane to carry sheet goods on. Here’s a universal example for $200, a nicer one meant for a specific truck is probably 3-4x more: https://wmastore.com/product/universal-drywall-plywood-mattr...
I've owned a few pickups over the years, owned my house much of that time, and can probably county the times I've needed to move plywood or other oversized lumber on one hand. Add a second hand for times I've moved long pipes or other oversized stuff that required flagging.