Jeff,
I suppose you'll get as many "slightly different opinions" as you get "responses to your post"...
Here's mine: China Bombs are a result of much more than just one issue. Years ago, tire manufacturers moved their ST tire facilities to China (cheaper labor) and there was a lengthy "learning curve" that resulted in many inferior tires on the market. Putting those "inferior tires" in a "barely adequate condition" created a hazard with a "bomb reputation". Chances are had the tires been installed with an adequate weight margin, they would not have failed as often, had they been better quality (initially) they would not have failed as often. Had they been BOTH better quality and used properly, they would have certainly not "earned the bad reputation"....
All that said, Goodyear Marathon ST tires were the "go to gold standard" for years. When they moved the manufacturing process overseas, the tires began to "earn" a bad rep and eventually resulted in multiple recalls. That, IMHO, wasn't a result of changing the weight standards for tires installed on trailers, but a result of inferior quality. On the other hand, Carlisle built a plant in China to manufacture their RH and later HD lines. Both have excellent reputations in "most" RV communities, but is that a result of "Carlisle owning/supervising the plant or of installing adequately rated tires as a part of the "learning curve" by RV manufacturers in the states ??? I can't tell you, but I do know that at the time, Goodyear Marathons were being replaced by Goodyear Endurance tires. The Endurance line is manufactured "in the USA".... Co-incidence ??? Probably more "incidental" than we'd suspect, but is that a result of "outsourcing the supervision/quality control" by Goodyear as opposed to the "in house supervision/quality control" by Carlisle ???? And how much does the recent change from "inadequate" to "adequate" to "additional reserve capacity" that's been mandated by RVIA factor into the current situation as opposed to the reputation that was "earned" by past tire problems? There was a time that LT tires were attempted (to get better performance) and that seems to have fallen by the wayside as the ST tire quality/fitment become more reliable....
I don't think we'll ever gain access to the "in house records" of any ST tire manufacturer. That "secret data" just isn't available....
My guess: It's a combination of inferior workmanship, cheaper quality materials and the RV industry "cutting corners with inadequate tire ratings"... which contributed how much? We'll probably never know, or even get access to the data to begin to find out......