I've been wondering for several years why no one has bothered to make library parts fab to order similar to books on demand. Mfg would not do this directly, since they make much of their profit on parts.
There are places like eMachineshop that fab to order. If one had a library of tractor parts, there is no need to have inventory, just order the part fabbed. The price would be high, but then tractor parts are not exactly cheap. This would be useful for those out of production rarely needed and not exotically manufactured items-- fancy heat treating with special alloys would be problematic, but simpler items are surely easy to library and produce to order (indeed, I suspect the tractor mfg actually do something like this, when inventory runs low they make a short run of a few parts to refill the inventory-- and the supply chain rakes in huge profits if the parts sell).
Local parts printing is the ideal end point of course, cut out everyone but the materials supplier and the IP source (you did not think you would avoid DRM
did you?).
Indeed, delving a bit deeper into the space at the bottom a Forge of God (materials forge) would have interesting effects-- such ending the "War on Drugs", big pharma, diamond merchants, simple semi fab,... replicating high cost low mass more or less structurally simple materials at low cost.
