What justifies the price of a USA-made PRS guitar are the preparation of the materials, the manufacturing process, and the attention to detail.
Those of us who have been fortunate enough to visit the PRS factory in Stevensville can testify to the lengths that PRS goes to in order to provide a consistently high quality product.
Preparation: PRS has a top-notch procurement and grading system for the woods used in their guitars. They start with quality ingredients and they season those ingredients perfectly. The wood drying rooms aren't just enormous, they're high-tech. Wood isn't just kiln dried like it is elsewhere. It's specifically dried to a measured 6% moisture content. I don't know of any other guitar maker that is doing this.
Manufacturing process: PRS claims it takes a month to build a guitar neck from a raw piece of wood. They dry the wood, do a rough cut of the neck shape, then put it back in the drying room. Then they do the basic back carve, and put it back in to be dried again. The month-long estimate is not an exaggeration. This is a drawn-out process that takes time, but ensures that the neck will be incredibly stable when it's finished. I don't know of any other guitar maker that is doing this.
Attention to detail: While at the factory I watched a CNC machine at work, and saw it drilling holes for switches and knobs in a guitar body. It went through a successive line of drill bits, smaller to larger, making the hole bigger with each bit. This struck me as something I would do when woodworking by hand, in order to improve the precision of where the hole was placed, but I was surprised to see it done even in an automated system like this -- I have seen guitar CNC work done elsewhere without going to that trouble. I asked about it and was told PRS did it that way to reduce bit travel and prevent chipping. I don't know whether other manufacturers do the same, but it struck me as being one of many small details that take more time and effort but add up to a more consistent and polished product. PRS manufactures its own hardware, from brass-impregnated nuts to aluminum stoptails with brass inserts to their own knife-edge tremolo system. They spec their own potentiometers with custom tapers. Paul himself studied the electrical and magnetic properties of guitar pickups so thoroughly that the research his team produced led to the founding of
an entirely separate company that provides image enhancement for medical industry and the military. I don't know any other guitar maker that is doing all of this.
To put it bluntly: I don't know of another guitar factory on earth that has both the means and the will to put as much effort and technical prowess into the guitars they produce.