Atlee,
First, I think the trailer tire market is such a small and isolated market that what happens there doesn't change the perception of the marketplace as a whole. Goodyear's reputation is NOT appreciably affected by the failures in the Marathons.
Second, I think "people" have short memories. Witness the Firestone situation a few years back. It did not take very long for "people" to forget what happened and rank them highly in surveys.
Third, I think the problem is one of design - what materials are used where and how much - and NOT a "Quality" issue - as in either consistency from individual product to individual product or a flaw in the manufacturing process -in other words, a "defect". Because trailer tires are such a niche product, it is likely the tires are NOT being produced on the latest equipment. That equipment is reserved for LT and other high volume tires where the profit margin and the overall impact on image (as you alluded to) are greater. That limits what technology level can be used.
I note with great interest that only 2 out of the top 10 tire manufacturers produce ST tires. I think this says something about the niche itself - either the profit margin is too low, or there are fundamental issues that keep manufacturers from entering. I suspect both.
Fourth, I don't think Goodyear is intentionally putting "garbage" on the market, it's just that the expectations have been raised over the years and these tires haven't kept pace. The level seems to be acceptable to the greater market - ie, trailer manufacturers, the ones who buy the bulk of them - and that doesn't apply pressure to tire manufacturer to step up.
But there is good news. Goodyear does have a system in place to track the performance of their products - the warranty system. They examine every tire returned to them and catalog it in a database for their engineers to examine.
But if a person with a tire failure doesn't report it, how is Goodyear supposed to know? EVERY tire failure should be reported to NHTSA and to the tire manufacturer.
And lastly - doing the math: You may think 4950# is well away from 7K - BUT - if we consider side to side and front to rear weight variation and a 15% un-used over-capacity, AND factors to raise the speed limitation to 85 mph, then the axle loads need to be less than 7900# - which is well over what your trailer is capable of handling. I think trailer manufacturers have a role to play in this as well. They need to provide tires of adequate size to cover ALL the things that make for good tire performance.
