I think the problem is using better quality materials doesn't really show up or become apparent unless you are already breaking kingpins all the time. It would take a significant marketing budget to convince people to spend 50% more on your trucks for small gains in material strength/quality, and that marketing will quickly wipe out the advantage of potentially higher sales. Will people see it as worth it when the majority of people aren't breaking them often enough in the first place to be concerned with it?