I am amused by the dispute between those that seem to be defending China made tires and those who are not. Having been RVing for decades, always towing a trailer or fifth-wheel, I have also nearly always had Goodyear Marathons on them. My trailer weighs over 11,000 Lbs, and close to 12K in travel trim. I have only (ever) had one trailer tire failure and that was the result of getting a flat from a nail in a tire. (I had three blowouts when I was using Firestone Steeltex tires on my truck, that were all made in the USA.) I should also point out though, I have never owned a Marathon that was made in China; nor will I.
Whether anyone likes any particular tire or not, I want to point out a couple of things. Regardless of who makes a tire its longevity, and whether it is prone to failure is not just a factor of the tire quality. It is also affected by high heat. Most trailer tires should not be driven over 65 MPH, yet I constantly see people towing at 75- 80 MPH. I also see people towing while their tires are clearly under-inflated, both are factors that will certainly cause premature tire failure. In addition, we have all seen people drag their trailers over obstacles that can damage the tires, clipping curbs with the trailers, and hitting things that make us all wince.
It is my opinion that a good deal of early tire failures don't just come from tires made in any particular country, but from our occasional carelessness. Yes, I know none of us want to think we a fallible, but we are. Sometimes a tire failure is our own fault.