There are too many that never experience the problem. A retired tire engineer who is on his second or third set of Goodyear's explained to me the problem as pressure, pressure and more pressure. Now, is it all pressure probably not, but it probably contributes a large element. Tire inflation charts are meant to be used as a guide not as a law. Most, who I have talked to are inflating just to the actual weight and adding nothing for anything and ignoring the recommended pressure by the coach manufacturer.
I know you said the shocks are fine, but at 44,000 miles I have to question their performance. They may not be leaking, but I feel confident in stating they have lost some of their performance, it is only natural. Couple that with most MH's chassis are under shocked in the first place and you have a recipe for a problem.
I sold a lot of tires, in a lot of different brands and those who brought their cars in with similar tire wear patterns that people with MH's call rivering, we would say indicated suspension problems. I learned early on, that telling a customer he wasn't inflating his tires to the proper pressure was also a recipe for disaster. It is truly amazing how many customers especially the MEN get angry when someone ever implies that they are not doing what they should be doing, and there you have it. The real reason why every one is told that their suspension, alignment, shocks, air pressure or whatever is perfect. So it has to be defective tires.
I think I will put my flame suit on now.:b