Earlier quoted context omitted.
Because the pickup isn't a work vehicle. It is a statement, a bit of fashion. That's where the market is. People want to look like they need a pickup. In reality, they would be better served by a minivan. They are why every truck has back seats. A more honest answer is probably to get the smallish SUV and buy a trailer. An 8'x4' metal trailer, with full wheels, will let you haul the wood/stuff those few times a year…
Good grief the bed heights are ridiculous now. Forget about reaching over the side and grabbing something without having to climb in: and I'm 6' tall! I've mastered this maneuver where I jump up and land with my stomach over the edge of the bed. It's uncomfortable but I can actually reach something. My father is three inches taller than I am, but it was still something of a revelation for him a couple of weeks ago wh…
There may be an unmet demand in the US for some of the smaller vehicles. Most of the big car manufacturers here in Europe offer vans: Ford, Vauxhall/Opel, Mercedes, Renault
Here's some examples if you're interested in looking at some of them -
Smaller car-vans - like the Ford Fiesta, and Vauxhall/Opel Corsa both have (or used to have) van variants.
Small dedicated vans - like the Ford Transit Connect, Vauxhall/Opel Combo and Volkswagen Caddy
Regular vans - like the Ford Transit Custom, the Vauxhall/Opel Vivaro, VW Transporter
The Larger vans like the Mercedes Sprinter and Ford Transit you may be more familiar with.
In the UK where I am - Rural postmen, as an example use case, make heavy use of vans like the Transit Connect and Vauxhall Combo as the fleet vehicle of choice.
Regular Tradesmen (plumbers, builders, plasterers) for example tend to use tall panel vans like the Transit or VW Crafter as their weapon of choice.