[mcl fabrication]

When it gets to the point of static models I understand what you mean. The question then will be can the same licensing that is used to make a 1/28 scale truck (KW) be used to make the same truck in a larger scale 1/14.
It all boils down to supply and demand, There is not enough people in the America's that is into this particular hobby. Though it is growing fast but not fast enough for Tamiya or any other company to make a larger variety of American Themed semi trucks.
They are a corporation. The most important thing for them is quarterly earnings (basically make money). There's just not enough of us to be seen as profitable. Once Mini trucking in North and South America grows to a point in which sales rises to a all time high then they will see that there is a market for new model trucks.