They could even implement what that Israeli EV startup wanted to do, quick charge by physically swapping the pack.
If enough contractors use electric pickups, I could see a contractor supply shop also renting these range extender packs and swapping them for charged packs. A construction supply shop is a good place to do this, as it already has storage, loading bays, weight carrying equipment and people used to heavy loads.
That kind of defeats the purpose of having the truck to in the first place.
For a contractor doing repairs your value is the fact that you have the replacement part on the truck. That means you have bins of sensors, motors, valves and such sitting around because every 3 months you need each and the customer needs it fixed now.
For a contractor doing new work there are less materials (that is generally delivered by a different truck), but you still have tools.
CF is expensive, but I'd expect it to last longer than steel - it won't rust.
The thing that makes me nervous about CF cars is how quickly they burn. Look up videos of Lambos on fire; the entire car is engulfed in a matter of seconds. Epoxy holds carbon fiber together, and it's very flammable.
You could avoid it on cars, but for a truck it makes a lot of sense.
It'll be interesting to see how the carbon fiber body survives. It will probably depend mostly on whether the trucks wind up supporting maintenance work or putting around to check out faulty equipment reports.