I don't know how that is going to play out. The metal 3D printer I have seen was quite incredible with the things that could be made out of stainless steel powd

I don't know how that is going to play out. The metal 3D printer I have seen was quite incredible with the things that could be made out of stainless steel powder but the price of them doesn't seem to be coming down at the rate we normally expect with electronics. I guess once somebody works out how to do it as a desk-side or small factory, high volume situation it might turn things around pretty rapidly on a precision injection mould but there is little incentive to develop such a thing while we still have access to the chinese market, even for complex moulds. You're right about injection mould design being a dark art, there is so much to be concerned about that just getting something to fall out of the mould cleanly might as well be magic.