AS I have said before the same cheapest pieces of junk tires regardless of where it is made is installed on tow behinds, park modles and fifthwheels as OEM unless an optional tire upgrade is offered.
All park models are only every towed once or twice during the trailer useful lifetime and most TT tow behinds are only towed a few short trips per year.
If you are purchasing a fifthwheel for many 10's of thousands of dollars and plan to tow it thousand of miles every year why would you not insists on the replacement of the display and delivery tires for brand name quality rubber before you take it off the dealers lot.
A few years ago I was walking through a trailer park and happened to glance over at brand new TT with a huge sidewall bulge in a Towmaster tire and then not long later out on the same walk I went by a newer park model and could not help but notice the identical tire right down the the same size on the park model.
It was then and there I realized the OEM's only install the very minimal SPEC'd display and delivery tires and could not care less what happens with the tires once the unit leaves the factory.
And if I was the bean counter in that factory I would make the same decision as the vast majority of trailers never are towed enough miles to ever have a tire failure that make the owner suspicious enough to investigate further.
When a newbie make his first post on here asking about blowouts of 2 or 3 year old ST's that just "POP" for no apparent (SIC) reason that's when we can start to educate the newbie about tire nuances.