Judging by how quickly these sell and for how much they sell in the secondary market I still say that if they doubled the size of their exclusive runs, they would make "double mint" and have even more money to invest in future projects. 
Given the nature of how the Trainworx tractor cabs are decorated (i.e., using clear body castings) and how complex some of the detailing and paint schemes are, it is quite possible that Pat has secured a smaller outfit that may not be able to ramp up the production on the more intricate models as easily as a larger manufacturer could.
While manageable from the importer's stand point, it is quite probable that the smaller production runs have also driven up the per unit model pricing.
Ever notice how the time span between Athearn announcement and release dates appears to be longer than those for many other importers?
Trainworx tends to deliver products as quickly, or in some cases faster than the larger outfits, and Pat's scheduled delivery dates tend to be fairly accurate.
None of this would be possible if the order quantities were increased beyond the Chinese manufacture's production capacity.
