The other aspect that may be keeping them from taking more stringent action is that they cannot link any of these issues to a crash. They would also not be able to link them to a death or serious injury. Their main responsibility is to reduce crashes, injuries, and deaths. Beyond that, we are talking about property damage here. There is commonly some damage to the trailer from the force of the blowout. One could argue that the damage is equivalent to being in a crash. But it is not a crash, and the injuries and deaths are related to crashes, not to property damage from the sudden release of pressurized air that carrys portions of tires with it with sufficient velocity to do said property damage.
So until someone is injured or dies (perhaps a motorcyclist adjacent to the tire when it blows), I don't think you will be able to get standards to change. The only thing you would be able to do is get individual lines recalled if it were apparent they did not meet standards.
