We have seen a history of over production of factory painted kits which were made in quantities that the increasing movement of modelers to RTR saw kits to be over produced. These gluts lead to huge discounting; remember P2K Mather stock car kits going for only $5?
I can see that the current escalation of of retail pricing, even on reissued RTR cars from tooling made decades ago, will garner interest in finding these older bargain kits. I especially see new interest in Branchline 40' and 50' box cars, but Red Caboose and Intermountain cars should reach similar interests.
With an increasingly collective knowledgeable data base, these cheap kits offer an opportunity to do corrections that many modern RTR freight cars suffer from. Many new box cars arrive with obviously incorrect components applied from the factory. The interest in the correct components used on whole classes of box cars buoyed from those great lists made by Ed Hawkins (Who ranks up as high as Evergreen Styrene strips as to adding immensely to the importance of fine modeling). Instead of retro fitting correct components to a factory built car, the savvy modeler can incorporate them in the kit building process. The win/win aspect of this is great accurate models done at lower than market price for today's issued freight cars. An additional win is offered from the joy of kit building.