I think expense, not weight, is the reason these got cut. Good 1/4 plate steel that will support the truck no matter the odd cuts needed for prop shafts and exhaust fluid access etc gets near a couple hundred pounds, depending on the truck, but that's not what manufacturers usually make. They can stamp ridges in high tensile steel sheet and get 80% of the goodness at 1/2 the weight. It wouldn't have been a deal breaker on the fat lady here.
This is a low volume truck from a manufacturer that can't write off dime on any other product, using a body and frame the equal to any Gwagon. That costs $$$$$$$. They were bleeding cash, the final unit was over target cost already, they had to hit a timeline for deliveries, and they took a hatchet to anything a bean counter or marketing guy didn't think necessary, and development stopped before the product was totally baked.
We all view the world from our own experiences. After spending a couple decades managing projects for some rather large corporations, and having managed a plant myself, I see budget constraints all over the place in this rig. As a vendor, every couple years someone I report to gets promoted, fired or retired. Invariably the new guy comes in and starts to rant about how poor the facilities are and what an ass his predecessor was, and my response is always the same. It's safer to assume the guy before you was genius, that he got done what he did, with the budget he had, than to think this place stayed in business for 100 years and grosses 15b because everyone but you is a moron.
Money drives all busses.