Yea, so I think scale, both in volume and in number, is a huge variable.

Our cases are relatively small so they can be printed in a couple hours. And during the development phase, we are going through hundreds of prototypes. (The fit has to be just right, so if a part is 5% off, we scrap it and reprint.)

Also, I love that you mention the fiddling as an annoyance. My co-founder loves fiddling w/ 3D printers so outsourcing all of our printing would take away that hobby :).