Can't be too hard to just mount a wheel carrier in the bed, or swinging on the rear, and just use that spot as extra storage though. I don't know a single off-roader who doesn't mod their vehicle in similar ways to make up for perceived shortcomings.
If they are targeting sales to a small number of large fleets, this doesn't matter. In fleet operations, the driver will never ever be allowed to change a tire. This is simply not acceptable, insurance-wise. You will dispatch a second truck to handle the delivery and also a tire repair service truck.
An electric delivery truck is probably not even in the cards for small players, where gas or diesel is a better option all around.
