Sven:
Brian is correct once again. If I understand what you mean by 2-pin surface mount sockets (Leviton's Lev-O-Lets, for one example), you're talking a completely different animal. I don't believe any manufacturer has the requirements for such devices that would justify automation. So, for those and for 3-pin surface mounts, you're talking more parts and labor for the grounded.
A corporate type once asked me, with some annoyance, why isolated grounding makes for more expensive devices in commercial duplex receptacles but less expensive devices in power receptacles. Similar answer: different construction. In the crowded and busy guts of a standard-size duplex, we have to work harder. One solution is an insulator that sits against the metal strap, separating the ground contacts from the strap, and terminating in either a ground lead or a lug with a ground screw. By contrast, in a power receptacle that is mostly plastic body against metal strap, to even achieve a ground we have to add a shunt to the ground contact and rivet the shunt to the metal strap. Want the ground isolated? Leave out the shunt and rivet, and the attendant labor and overhead.
