After spending a great deal of time on RV forums, and listening to many many tales of tire woes, I have come to the following conclusions about tires on trailers:
1) Most trailer manufacturers use marginally sized tires. They pick a tire size that BARELY covers the load.
2) Some trailer manufacturers do a poor job of estimating the actual load on the tires. Not only do they underestimate how much stuff people put in, but they don't account for front to rear and side to side load variation - AND - they size the tire based on a 65 mph speed limitation, which is frequently violated. (Did I mention that trailer manufacturers don't normally inform purchasers of this speed limitation?)
3) There is a severe disconnect between trailer manufacturers and tire manufacturers. Trailer tires are usually sold by a wholesaler - they are not a direct purchase from the tire manufacturer. Trailer manufacturers don't do warranty on tires, so they never know how well the tires are performing.
4) Most trailer tire manufacturers are based on low cost producing countries - typically China. Not only does that mean that trailer tires are behind the development cycle, it also means that there isn't a good feedback loop between the consumer and the manufacturer, so it isn't recognized that improvements are needed, nor can improvements be tracked once they are made.
5) Many folks aren't used to the level of maintenance that trailers require. They are used to car and trucks produced by HUGE manufacturers with excellent feedback systems, that have developed their products durability to the extent that maintenance is hardly necessary.
By contrast, trailers are way behind in this area - as are the tires. There is a whole new learning curve that needs to take place for trailer owners, that isn't present in cars and trucks.
Not to mention that most folks are not capable of recognizing the difference between road hazard related failures (which are more or less unavoidable and will occur regardless) and durability failures (either caused by the tire's shortcomings, the vehicle manufacturer's shortcomings, or the owner's shortcomings). This clouds the picture to the extent that ANY tire would be blamed for things that aren't the fault of the tire.
**** In summary, the trailer tire situation is confusing and complex and getting a solution to an individual's problem requires work on the part of the owner - weighing the trailer, for example.