OK, a couple of things:
First, is that in the truck market, it's the buyer who specifies what tires are put on the vehicle - EXCEPT for vehicles not purposely built for customers. In those cases, it's the vehicle manufacturer who decides what tires go on.
In this case, the chassis was a bus chassis, which is usually used for intercity bus service. That is start and stop type of service, which the tires were designed for. The problem was that RV converters bought those chassis's and didn't change the tires out for something more suitable for RV service.
Ergo, I don't see how Goodyear was involved in the decision as to what tires were applied.
Second, how is the chassis manufacturer or the RV converter not liable? Maybe they are, but they settled earlier to avoid the bad PR.
Clearly Goodyear could have done a better job of handling this, but I just don't see this as a "defect". It's a "poor job of selecting tires" type of thing.