Lots of comments on this question but there are some points not mentioned.
It is well documented that over half of the 5th wheel trailers have a tire and/or axle overloaded.
Multi-axle trailers place internal structural forces that try and tear the tire apart (tread and or belt detachment) that are 20% or higher than the forces seen on vehicles with tires at the corners.

In multi-axle application the tires should be set cold to the pressure molded on the tire sidewall to decrease the special side loading forces. Note I said "decrease" not eliminate the higher loading.
If a tire looses air, few people become aware of it before it looses the 20% that qualifies it as being flat because they can't feel the problem and don't have a TPMS. Before you claim you check your tires every day I would ask why you don't check your engine gauges as you leave the campground and then shut off all the gauges to save energy. After all you have already checked oil pressure and engine temperature that morning so who needs to worry about the numbers when driving down the road.
Even when documented that a tire was run after loosing most of its air many owners still want to call the tire defective (see my blog post "Blowout a real life experience".

for more pictures and complete examination information.
I wonder what the response would be if I complained about my GM or Ford or Mercedes or xxxx engine blowing up after I also admitted to exceeding the red line limit for the engine. Would you still accept my claim that the design or manufacturing of the engine was defective?
When a tire fails there is sometime significant expense involved because the trailer, unlike your car or pick-up only has some thin plywood or fiberglass that has to tolerate the thrashing tire pieces.
Who made the decision to not have even some .060" steel with backup steel support?
Who made the decision to pay more attention to mirrors and lights in the ceiling of the RV than confirming that critical wires were protected?