Topics like this... I cannot help but think about this scene in Independence Day
But in all honesty, its pretty simple econ.
A business sees an industry they might be able to do profitable business in, and they jump in.
If homework is done right, the actual cost for the products is pretty straight forward.
Each business has to cover expenses AND make a profit.
Add in the potential "market" for such a product, and the profit margin may be artificially inflated.
If it sells, great for them. If it doesnt, they better figure out why, and if it is associated to cost, they better react correctly.
On the consumer side, its pretty simple as well.
Nobody wants to spend more than they have to.
So everyone price shops, kicks tires, etc.
This particular industry is pretty interesting though, as the consumer base is VERY broad.
From the person that hardly spends a dime, to the person that cannot seem to spend enough.
Neither have it figured out more than the other, and often, neither spend more than a few nights a year in "expo" mode.
Most troubling for the "custom" builders like myself is that the VAST amount of would be clients out there buy and sell rigs, literally, like they are going out of style.
Ill argue all day long that the best client for a custom built camper is one that never intends to sell. Those are few and far between.
My question, is it worth it to spend the $$ for a capability that may only get used 1% of the time.
In your case, it has little to do with capability, and everything to do with capacities.
According to your numbers, you are running a VERY thin margin for tires and axle ratings.
A 300# margin for the tires and axle is a terrible gamble.
IMO, you need more tires and more truck for that load, even for pavement travel.
Sustained off road travel, good luck....